Training plan

Hoping to clear up a couple of questions i have regarding training plans. Im about to start the build me up.

1 It is my understanding that i cant do two work outs in a day- even if that work out is only 30 mins long?

2, do all work outs require the same rest period afterward i.e 24hours? Is the time of rest listed anywhere for each work out type? 24 after a 30 min workout is generous.

3, zwift shows when the workouts are available from, i assume i need to complete these by the end of that week before the workout is locked?

Sorry if this has been answered elsewhere.

Ta