Girls und Panzer has several manga series:
How does those three relate to the anime series and which chapter covered in anime series and OVAs? Is there any differences between anime and manga?
Girls und Panzer is an original anime and the GuP manga is an adaptation of the anime. Though the manga came out earlier in June 2012 as promition to the anime while the anime came out in october 2012. Both GuP anime and manga are practically the same except for some differences in perspective and events. The anime focused on Miho Nishizumi's perspective while the manga focused on Yukari Akiyama's.
Girls und Panzer: Little Army is a prequel manga for the anime and manga that came out in August 2012 about Miho's past.
Girls und Panzer: Lovey Dovey Panzer is a fan-made 4-koma web manga series done by Nii Marco about the GuP characters and it focuses on comedy. From that, eventually Nii Marco was hired by the GuP staff to make an official manga 4-koma series titled Girls und Panzer: Motto Love Love Sakusen Desu, sort of sequel to Lovey Dovey Panzer. Though it's still focuses on comedy.