Training plans - timing

Hi, i recently joined Zwift and is trying out the training plans.

I noticed that I am not able to pick the time of when the time starts, so i missed one of the workout.

Also, for the next workout in the plan, there is no option to pick the time as well.

Did I miss something or is there a way to set the time?

Moreover, I tried deleting the plan and then re-pick it. The workout that I missed initially, is labelled as “unavailable”. There is no option to pick it.

Is there a method to change to the workout timing and also to re-do a missed workout?