If there are any words you dont understand, you could put them in the search on here and lots of previous posts will come up.
Heat spike is the heat felt by your client when gel is maybe applied too thickly or their nails are a bit too sensitive.
Flash cure - I think is where you can cure the gel for 10 seconds or so to lightly set it.
Rebalance is a term used for maintenance where you are doing more than just infilling the cuticle growth.
NSS - is a term used for a non standard salon.
Hope that helps.