Triphasic chart question - is mine?

[patienceiav]

Hello ladies

I'm sure this is an often covered question but I've never really understood what a triphasic chart is during all my months TTC ! It means 3 "levels" of temps, right ? Is there some guideline like "between X and Y temp is one level, and you need X amounts of temps on that level before going up to Z temps" sorta system?

Also, is it even fesable to have a triphasic chart while on progesterone ? This is my first month using a prescription and i know it'll likely affect my symptoms and my temps, but how much I wonder