Spells:
These can be fun, though generally people don't like being randomly spelled! xD

Mask spell: Mushrooms on trees. Little icon will pop up showing a deer eating mushrooms when you're close to a tree.
Antler spells: Little icon will pop up with a deer rubbing a tree when you're close to a tree with pinecones. Eat the pinecone that drops when you rub the tree to get a spell.
Pelt spells: Sit by a sleeping deer for about 10 seconds.

Body language:
Emotes are found when you click the blue square and/or the orange square.

Bowing is a greeting, tilting your head means you didn't understand.
Lowering antlers can be taken to be aggressive. It may mean "go away".
Sadness, amazement, ROFL, and scared all mean what the look like. x3

Scratching generally means 'come here' or 'sit here'.
Taunting and rearing [next to scratch on the emote bars] can be taken to be aggressive.
Yes/no are what they seem to be.
Dancing is just for fun. ^^

Bellowing is just for making your picto pop up a little more if you want to be noticed [just don't do it too much]. Listening makes the pictos easier to see.

RPing:
We generally create characters around here, though if you just want to play the forest as what it was originally intended for [relaxing screensaver], nobody will object. :3
Many people enjoy the forest by creating characters. We play as those characters in the forest, and have them interact with other characters here or in-game. ^^

Mostly, you just have to find your own way of playing them game. Be conscious of other players, but it's different what makes this game fun for each person. You're probably still a fawn, so people won't mind if you don't understand yet!

I'm glad. ^^
You'd post it under the biographies section, in the little drop-down list when you create a blog. You can look around for a few examples of how they're set up. :3