Did you like the first main season? If you haven't watched it, go there first.
This OVA is composed by two stories, supposedly from two chapters taken from the manga. Not much happens here, it could be avoided, but if you're a fan and already love the story of the Bookworm girl you can leisurely add this to your watching list.
The first one is more interesting than the second and introduces new characters that are intrigued by the girl Main and as to the second one I'll just say it's about a joyous ocassion for some of the secondary characters.
Consider this as a anecdotical appetizer before continuing onto the second season.