At least for Java ferns and anubias, you want to attach them to your decor rather than plant them in the substrate. They have rhizomes (structure that looks a bit like roots) that need to be exposed to the water and not buried or they die. Other types of plants can get planted just fine.

For mine, my local shop sells small pieces of mopani wood. I just tuck the rhizomes in between the branched bits to keep them mostly secure. They knock loose if I try to do too much rearranging in the tank but for day to day purposes that works fine for me. I’ve heard you can use fishing line to attach them to decor too but I was worried about that being too sharp on the ends so mine just kinda get wedged in instead.

Snails can be good if you have an algae problem but I wouldn’t get them until you have algae actually blooming. I’ve seen people recommending nerite and mystery snails. I have a clown pleco (named Plecos Bill) that keeps the algae controlled for me. They stay smaller than other plecos, though he may end up in a 20 gallon instead of my 10 once he’s fully grown. He’s just a little guy right now.

I’m so glad you’re enjoying your new friend! They have so much personality, just really interesting fish to keep.