Single exercise: perform one exercise then rest
Superset: perform 2 exercises then rest
Triset: perform 3 exercises then rest
Giant set: perform 4 or more exercises then rest.
Week 1: upper, lower and core splits using single exercises
Week 2: upper, lower core splits using supersets
Week 3: push, pull legs splits using supersets and trisets
Week 4: push, pull, legs splits using trisets and giant sets
I have designed the program like this so it progresses you through the 4 weeks.