Weeeell... giving you a list of ALL init utilization possibilitys is impossible, lol.
Now some things you need to know about init fields:
With init fields you can doo nearly all things that you can do with an external script (sqs file), but init fields are hard to write in, and most of times stuff you write there will not be recognized in MP, still init fields are good for short stuff like add weapons or set behaviours.. Important is sintax in the init fields, remember to divide each command or script with a ";".
..Only thing i can recommend you to do is to play around with init fields and add little scripts, you can also just copy and paste them for the begin. Try to add stuff or delete, change names of the units and so on, look at the command reference or at the editors depot, there is ALOT of example material that helps you start with all that.