Not much was added to the original anime. Honestly it just seems to be some way to prolong the show or something, but I just can't seem to find the value of this episode in general. There's a cliffhanger in the end though so maybe that means we can expect a season 2?
In short, this is just a Sakurai x Morioka slice of life episode. The whole thing is basically Morioka wanting to upgrade her pc and Sakurai offering her a hand at that. So they spend the entire episode upgrading the rig and building it. Not bad in overall, but not something significant either for an OVA.
What to expect: Gaming, Comedy, Blushing, Frustration, PC building tutorial.
What to not expect: Kissing, fan service, Any overall progress in the story.
That's all then. Cheers.