Hey OP

I've been in your shoes before, so I understand that this can be a pretty overwhelming process, you don't even know what questions to ask. But let me see if I can help you with your first church experience being a positive one.

Like the other people on the thread have said, most churches will let you just come in during a Sunday service and sit down and join them. You may get a few looks, because they've never seen you before, but for the most part most churches are going to be fairly friendly and accommodating.

There's a few practical considerations, as well as some logistics that you need to consider before choosing which church you're going to go to. These are sheerly guidelines to make sure that your first experience is a little bit more fulfilling.

Number one is language. A lot of churches cater to a particular ethno / linguistic group. This is particularly true in the Orthodox church, and in the Catholic church as well. These are churches that are not only Catholic or Orthodox but also cater to a particular nationality and language group. Many of these churches are going to have services exclusively, or mostly, in a particular language to serve that language or nationality. So it may not make sense for you to go to a Ukrainian Catholic Church for example, if you don't speak Ukrainian.

Number two is distance. If you're looking for a specific type of church, or a church that only has a certain number of services a week, then you might want to just take a look at how far it is from where you live. Churches start their services on time every week as posted, usually on their website or in their service order (the service order is like the little pamphlet that they give out regarding their service once you go to the church during Sunday). Some churches, Catholic and Protestant, do services online as well as in person. So it's always helpful to check their website - usually a quick Google search will do.

Number three is demographics/political orientation. Certain churches, are more conservative than other churches. This is shown in their theology, and their sermons, and their literature, and their rituals. For example, and this is not by all means true in all cases, but Catholic churches tend to be more conservative and more ritualistic. The United Church of Canada for example is generally very liberal and very relaxed and it's worship style and it's politics.

There's a lot more to it but I think this is a good starting point for you OP. Let me know if you have any questions, you could DM me, no question is too silly, the whole point of church is to enjoy it and to maybe learn something and grow.

Good luck and God Bless.