i have never dealt with bitcoin before, so i'm a noob and need a little help in sending.
i have recently opened an account with coinbase. i am ignorant about sending bitcoin. i've ask two sponsors to help with understanding, but they fail to give me specifics which i really need to understand, if i am going to send btc. after going through several informationals i understand better, but not all of it.

one of my questions was how i know when i can use the btc. i got an email stating it was ready, finally after 12 days i get to use it. so that got answered.

next is when i send. the send box reads amount which i put in. then reads mobile, email, address. is this where i put the string of numbers/letters for the wallet? the last guy i spoke with wrote that i needed to top it up. i have no idea what that means, i know there is a minor's fee. is that what he is talking about, and how do i know how much to top it with?

after i put the btc in and address for the wallet, what do i do next.
i realize i seem to be very ignorant about this, and i need specific answer, not just send it to .....
thank you guys for the help.