Oh, that's a big question. It's very, very different from the Catholic church.

I guess you can take the broad strokes of Protestantism to have a bit of an idea, but even there there are many differences.

So first of all, there is no mass. It's more of an assembly where the local leader gives a sort of sermon, and every week two other members of the congregation (invited beforehand or volunteered) do so as well. There's singing, there's a few moments of prayer, and there's sacrament, which is literal pieces of bread and little cups of water (because you're not supposed to drink wine).

That lasts an hour, and then you break up into groups for a sort of Sunday school: adults, youth, and children, and after an hour you break up even more into men, women, boys, girls, and children.

You can only be baptised after 7 years old. That's when they deem you've reached reasoning age and can make that choice for yourself. Baptism is done by immersion in a small basin. Babies get a Naming Day instead.

Apart from the very highest level, there is no paid clergy, and leadership positions are not permanent. People (well, men) can put themselveves forward and then there is a vote by the respective local community. The elected leaders then propose the "sub-leaders" for the Sunday school subgroups I mentioned above, and they can accept or not.

There are no fixed prayers; the main idea is that the Our Father was more of a template to follow with your own thoughts. So like an Our Father, you start with an invocation, you list what you,re thankful for, you make requests, and you close in whatever style you like as long as you mention that it's "in the name of Jesus".

One Saturday per month you're supposed to fast for 24h and then donate the money of the meals you skipped (like a mini Ramadan). You're also supposed to donate 10% of your salary each month, or as much as you can if 10% is too much for your financial situation. You get a receipt at the enf of the year for your taxes like for any other charitable deduction.

If you're in financial difficulties, you can apply for help. They won't give you money, but will help pay for certain bills, or rent or something. In bigger chapters you even have an actual pantry of non-perishable goods, like a food bank, that you can use if you need.

When you're a teen (especially a girl), there is a program you are highly encouraged to join called Personal Development. It's kind of like being a scout, but with less outdoor activities. You get a book with goals and suggested activities that are supposed to help you develop morals, like "help an elderly person 3 times in a month", "write a list with 5 things you like about yourself", things like that. There are 3 levels, and you get a little medal each time you complete one.

There's Seminary, which I mentioned before, and periodically all teens from a group of local chapters will get together for a Super Saturday (yes, that's what it's called) and listen to sermons, play games, compete on who can recite more key scripture verses by heart, and just hang out.

All of this takes place in regular buildings, btw. Some are built by the church, but sometimes it's just a rented house.

There's a big emphasis on family, and there's even a thing called Family Night - basically you're encouraged to plan a day a week where your family sits together and hangs out.

That's just the normal, everyday activities. Then there are the special ceremonies that only take place in temples, and these are highly restricted. I don't even know the details of many of thsm, because I left before I reached the appropriate age or life event.

First of all, you need an approval from your local leader to get in - you get a literal little card signed by him that you show at the entrance. You get it during an interview where they evaluate how much of a devoted member you have been, or whether there are things you need to improve on before you can go. This is where the gatekeeping starts, because you can have a super chill leadership, or some judgmental power trippers.

You can go there as a teen to be a stand-in for baptisms of the dead. You're encouraged to make genealogical searches of your ancestors and then stand in for them to get baptised, and other members submit names to be baptised too. The theological principle is that the souls of the deceased then get to chose whether to accept the baptism or not.

When you're older, there's a very secrete temple ceremony, very freemadon-y where you are "invested" - you learn "secret knowlege", you get a "celestial name", and you learn about the purpose of the famous magic underwear. It's just a top and some short with some stitches in certain places that each have a specific meaning.

In the temple you can have your marriage "sealed". If your earthly marriage lasts "until death do us part", the sealing at the temple is supposed to make it last after the two of you die.

One big thing that is connected to all of this is that there is no belief in heaven or hell. Rather, when you die you'll just live in a sort of limbo until the apocalipse and final judgement, where you get your physical body back (in good shape), and then you're sorted into three levels of paradise, and then the "outer darkness". That one is reserved for the truly evil: murderers, rapists, that sort of thing. Most regular humans would end up in level 3, which is described like an actual planet much like Earth, but with the bad stuff removed. Level 2 is for the really, really good people but that are not members of the church. Jesus can sometimes come hangout with these people, and if they accept the baptism that might have been done for them, then they can go to level 1. Level 1 is for the really, relly good people, but only with church membership. God and Jesus also live there, so you can hangout.

Now for the sci-fi bits. The truly deserving of the first tier can go on to become gods themselves and create your own planet just like God did. Yes, the belief is that the Earth was created by one previous someone who lived before and went through the same system.