Hi Mary30! I am pretty new to it too, but I was lucky enough to have someone snatch me up and explain all that right away, so I'll pass some of that knowledge on.
On the top of your screen is a button that says "Currency:, you click that open and it will say how many bells you have. Click your amount and it should open a little screen with the option to transfer. Initially it'll have your own name set up as the target, click to change that and it'll let you type in the name of the person you want to transfer to. Once you have that all filled out you just send it, and in your notifications box you'll get a message that confirms your transfer and the amount.
Hope this helps!