The stories in these two seasons follow after T2 and are built on those events. Fans of the Terminator film series know that each new film tends to deviate somewhat from prior films, but usually in a more-or-less believable fashion. T3 mentions Sarah Connor's death from cancer, and this is referenced here when the characters time jump from 1997 to 2007 in the first episode. The new time jump changes her having died earlier than the new timeline. Other references also tie in with various aspects of the films, even while possibly changing them.
In the TV series, Summer Glau is the Arnold replacement -- reprogrammed terminator sent back to protect John Connor. I first saw her in Firefly and then later in a few other TV series. All the roles I saw her play had a common thread -- she played a quiet but creepy character. Her terminator here matches as well. If you're a Summer Glau fan, you'll enjoy this role.
When I play BDs/DVDs for TV shows, I usually prefer to use a Play All option to string the episodes together for binge watching. These BDs do this automatically, and don't even have a menu to select individual episodes. When the disc starts up, it automatically plays all episodes (after the requisite FBI and other early screens). If you want to play a single episode, you'll need to chapter skip forward to the one you want and then stop (or go to menu) when it's done.
Even though the disc doesn't start at a menu, it does have one. When the episodes finish, you get to the Top Menu. You can also select it from the appropriate remote button. Bonus Features include things like deleted scenes (called Terminated Scenes) and Making Of features. Audition recordings for three main characters are in the first season's discs as well as dance practice for Summer Glau (who is mentioned as an accomplished ballerina).
The first season had only 9 episodes but the second had 22. If you buy these as a set, the (sale) price is pretty reasonable.