You might want to start by watching this video:
It reassesses the true intent of Polarised training. So if you’re an absolute beginner, do the 80/20 as it really was ment to be done.
If you implement 80/20 like that it is super easy. 4 sessions Low intensity, 1 session High intensity.
Low intensity is below AeT, high is above AeT.
If you don’t know where AeT is, use MAF method: 180 - age as a starting point.