Using segments to narrow down the data you are pulling from Google Analytics is one of the easiest things to do in Grow.
Click the blue 'Segments' button and choose a segment to have the id inserted into the segments filter. The id for for Segments is kind of weird. It is gaid::-4 with the number after the dash being the id. Luckily Grow will insert this for you, so it is just point and click.
More info about segments from Google here. It is pretty simple.
You can also filter in addition to adding a segment.
If you have any questions please email firstname.lastname@example.org or chat in on the site.