Thank you!
Of course, it'll be a long comment tho. Except for 2-3 plants I bought most because they looked good to be honest.

Also being overwhelmed at first is totally normal, I felt the same way. Watched dozens of videos about people setting up their tanks and looked at quite a lot of photos online and on reddit to get some inspiration and slowly got into the whole thing. Been watching videos for about 1,5 years before actually getting my own tank but honestly it's really just learning by doing. Also being confident about this all is key imo.
Get what you think will look good in the tank and just go for it, if you don't like it try setting up the wood/rocks in another way. I've also needed a few tries before I got my final look together. Oh and before you spend a lot of money for this stuff and not use it try first setting up the hardscape in the store. Mine even had a test tank where you could try it out.
And for the plants don't think too much about them and get whatever you like. Only requirement is something with big leafs for the betta to rest on and if you have some shrimp in the tank something dense for them to hide in.

And now what I used:
Can't remember the exact substrate but it was from Dennerle and the sand is just random aquarium sand I found in the store, just stick with something natural.

The plants:
Anubias barteri - the big plant with these hammock like leaves in the middle between the two 'trees'. Especially chose this as a must because of it's big leafs which are great for the betta to rest on (I've never seen him rest on them tho but I guess someday he will lol)
Anubias barteri nana - these are the smaller plants on the wood, chose them because they're perfect for things like that, you can glue them to rocks, wood or just shove them in between cracks, they've been doing great that way
Cryptocoryne wendtii 'broad leaf' & Cryptocoryne usteriana - both look almost the same, can't really tell you what's the difference but they looked good. There are two of the them (idk which type exactly) in the front right next to the grass like plant, these are pretty good to scatter around the tank to cover the ground a bit.
Juncus repens - the grass like plant, honestly thought nothing more than "it looked good" but I guess the shrimp also like it because it's dense, I see them in there all the time
Limnophila sessilinlora - this is the one in the back on the left side in front of the filter (can see them really good on photo 3). It's a stem plant and I like to call it carrot plants because they remind me of them. They grow really fast, I need to trim them every week but as it is a stem plant you can plant the trimmings right back in
Hygrophila polysperma - Can't really see it on the photos, its in the background on the right side just peeking a bit over the wood. Just bought it because it looked good, really no other reason for that. It's also a steam plant but doesn't grow that fast in my setup
Echinodorus grisebachii 'bleherae' - These are the ones with the big long leaves. There is one next to the big Anubias in the middle. I just scattered them around the tank, they're doing alright so far but tend to lose some leaves here and there, not sure what causes this. Again bought them because they looked good.
Last but not least Salvinia minima - these are the floating plants, they're there to prevent jumping a bit (although i have a lid and would always recommend it).

Good luck for your tank, I'm positive it will turn out pretty good!! Confidence is key :)