Are embedded sets supersets?

I didn't understand how Embedded Sets are to be performed.

Are you supposed to complete the Static exercise before the Strength exercise or do them in a Superset fashion?

e.g.

In Sequence

FL 15s, 15s, 15s, 15s (rest 60s between sets)

rest 30s - 60s

Tuck rows 3

OR

Superset

FL 15s

Tuck Rows 3

rest 60s then repeat Superset 3 more times.

The superset version would be much harder.

I'm also wondering if it would be a good idea to progress from the Sequence version to the Superset during a SSC.

The book and all the basic strength WODs are clear on the execution, but to answer your question: you will perform the sets as supersets. Using your example moves you will start with a 15 s FL variation, rest for 10-20 s and then perform the FL rows. Rest 60-120 s between supersets.

If you're working them in a sequence fashion, you are working the static and dynamic work separately, which defeats the purpose of embedded sets. Although, working FSP and FBE on their own definitely has its place.