Nakamura Women's Bicycle

Womens Nakamura road bike ~ I believe it’s a medium frame. Lighly used; Took it on a few river pathway rides and now im moving out of province and dont want to deal with moving it. I have bought a new back tire and chain. Sometimes the chain comes off but “the Bike Shop” has told me it’s all good and that I pretty much dont know how to do an easy fix for this or adjust my setting etc. Moving on the 28th