SBC Cam break in questions for small block chevy?

Ok, so I have this DVD by Boxwrench that tells you how to completely rebuild a small block. I am very close to starting this thing up for the first time, but I'm a little confused on the cam break in period and what damage I could do. The DVD says to run the engine at 2000 rpm for like 5-7 minutes, but my question is, when trying to start the motor for the first time, i assume it wont fire up perfectly the very first time, and it will take a few tries before i get it right and timed. so how many times can i try starting it and have it rotate all the internals until i went past or damaged the cam for its cam break in time? PLEASE HELP