Budgeting for a club?

Hey, I am a treasurer for my club and we are looking for sponsorships from outter companies and influences. But we have to prepare a budget for our upcoming events; since i am the treasurer, i am the one who does this. The thing is that i have not yet learn the concept of budgeting. Can anyone tell me how and what to do? if websites are avaiable, that would be awesome. Thanks for all the help guys and gals. Really appericated.