It's really easy. You patch a JUS ROM (Remember you need 2 roms, one clean and one patched) whith the DPSPATCHER and the DPS file on the WIKI of the JUS TRANSLATION PROJECT (DFF's one). After that you rename the clean rom to old.nds and the translated one to translated.nds, you run the patcher and a new nds file will be generated, put it on you microSD, boou up you DSTT and launch the rom.