step to root advan vandroid S35D

Advan Vandroid S35D is bearable, already kitkat, but still contained a shortage, the size of the RAM, the ROM is very small, the effort to root would be done, but there a little problem before root in this android, perhaps the master knows how to backup ROM on android, in recovery mode contained no menus backup / restore, thank you.
Model Number : S35D
Android Version : 4.4.2
Build number : WG3588-S35D_V1.0-2015.03.12