Can i replace the stock rom?

[fungaming]

Hi, everyone. I have got my jxd s7800b and wonder whether i can replace the stock rom because i wanna larger space. Although it works smoothly on the major games, i'd like to challenge my device. The problem is i do not know how to do this. I just heard it before.
Looking for help.

[Frendminge]

I checked on xda and there is custom rom available for your device. Just root your tablet and you are ready to try out custom rom

[Neoplan]

I am doing a debloated rom (my very first) from the last stock 4.2.2 rom that geekbuying put out and everything is working except play store closes immediatly...any ideas on why? This is for MK808.