Subscribing
A word of warning, note in the above window the number to the left of the group name is the number of messages currently on your ISP that have message number higher than the last message you downloaded. Which would be zero if you just subscribed.
You may want to modified the preference file to limit the number messages downloaded during one connection. In the above example you would download 100 messages from this group. You may want to reduce this number while installing/check out Lollipop.