Howto pause sleep ativity

Assume this situation: I slept from 23 till 3 o'clock, then was awake from 3 till 5 o'clock and slept again from 5 till 7 o'clock.

The Venu 3 seems not to register that I was awake and had read a book for two hours. Garmin Connect shows that I had a perfect night from 23 till 7 o'clock.
Workaround: Shaking my hand every two minutes helps the Venu3 registering that I'm awake, but it does not help me falling into sleep again.
Question 1: Can I somehow inform Venu3 / Garmin Connect that I am awake (and pause the sleep activity)?

When I edit my sleeping activity at the next morgning in Garmin Connect, then I can only edit the start time and the end time of the sleep activity (what would cut the correct sleeping time). But I can't insert a break into the sleeping activity.
Question 2: How can I insert a break into the sleeping activity?