It all depends on the size of the reel and the weight of the line. I hope "they" sold you a matched/ballanced outfit...
Anyway, one way to go is to load the flyline on the spool first then load the backing on top to fill the spool. Then head down to the local soccer pitch or open area where you can strip it all off and reverse the loading...Backing on first then the flyline. The flyline box usually has the necessay basic knots to get it all in working order...if the knot doesn't look right, tie it again! Your local shop can be a real help when your just starting out.
As you progress and add specialty lines to your list of gotta' haves, you will probably go to what's called loop to loop connections...to ease changing from one line to another.
'Sounds like it's time to do a little home work and read up on the basics and ask alot of questions...find a shop and if you take care of them, they will take care of you!
Good luck and wade safe!