It doesn't really go into how they beat the drug test, he just talks about how they randomly test from the start of training camp to the end of preseason. You only get selected once during that time, as long as you don't pop hot during that test you are good to do what you want until the end of preseason. If you pop positive you go into the drug program. If it is for marijuana, you can continue to pop. You just stay in the program and will get fined for popping. If you pop for anything else, i.e. opioids, PEDs, etc... you will still get suspended.
What they didn't cover is that they randomly test weekly during the regular season and there is no, one and done. You could get randomly selected every week during the regular season.