There's a list of possible sides and dangers BUT assuming you're "normal" it's not that big of a deal. Just run it once or twice a day at the same times daily (fasted AM and mid day). Start around 40-50 mcg and work your way up. Less than that will suppress you and give you a lower level than you have naturally (not cool). Some people like to pyramid up and then pyramid down. Others just go up then come off. Average time on is about 6-8 weeks for beginners.
The suppression of your natural T3 is going to happen and there's some debate on how long before that recovers. Most would say that you'd be back to even around 2 weeks or sooner after you're done regardless of how you ran it.
FYI, it's is not some super fat burning miracle drug either. You could take T3 at 100 mcgs a day and 24 mgs daily of Albuterol and without a proper diet protocol in place keeping you in a deficit and timing your nutrients you wouldn't see much change at all. What you did see change would come back on quickly also since you don't have the diet protocol to maintain your fat loss progress.
Not to mention T3 is a non-sparing burner. It'll burn muscle off just as fast as anything else. Test dose needs to be kept higher, protein needs to be up also to combat the potential loss.
So get your diet on point first then proceed with the PEDs.