title says it all.
Just as Hornet said, you cannot download entire episodes or series onto your computer. When you have a paid subscription, you are granted the streaming rights to the shows here. You can access them all here only on any Anime Network app. supported internet streaming device.
Most of the anime streaming sites have gone away from offering download to own episodes. The logistics of offering that service are much more complicated when you factor in things like different operating systems, competing formats (which is made even worse by the explosive growth of mobile devices), DRM requirements, etc. Not to mention, download to own rights are often separate from streaming rights. If you want to download en episode, you will need to access iTunes, PSN, Google Play, or other services.
Or manually record the stream as you watch it.