If you're not sure just how to use bitshares:

Easy way of doing it is making an account at https://openledger.io/
Make sure your header of the site looks like this:

If your header don't say switch to advanced then you need to click switch to basic
You will then get a page that looks like this:

You find your wallet for the currency you want to use and deposit to that.

Then use https://blocktrades.us/ to buy SBD and send to your account.
Or you just send SBD to your account if you already have it.

https://openledger.io/market/ZAPPL_OPEN.SBD

If you run into any trouble let us know and we will be more then happy to help you out.