Not a stupid question at all! That same thing stumped me for some time, honestly, it's kind of confusing! But see how to the left of this everyone has a little mini profile? If you click on the number of bells someone has, an option pops up to transfer tbt!
And would you be available to trade tomorrow?

I'm about to head to bed since it's late here, but if there's anytime tomorrow that works for you I should be available to trade!