F1 to H1B

I'm an international transfer student... I just finished my OPT and transferred to another school and enrolled in a certification program. i've been offered a job.... but i'm still currently on f1...they said they're willing to do sponsorship...so how does this work so i can start working immediately?

It doesn't. I assume they already have labor department certifiction for the position. They can apply for the H1B on an expedited basis, if they choose, for an additional fee.