Stem creation-separate guitar and synth organ

Hi everyone I am new to FL Studio. I am working with some reggae and psychedelic rock music. I am trying to make some jam tracks with some known grooves to get me going on some street busking .... I find the music i listen to currently gets me in the zone faster than creating from scratch...I tried creating a few song stem projects and generally, it is good but the electric guitars and synth-keyboards are on the same stem. Further iterative stem-create attempts do not fix this. I tried Moises and it was a bit better ... any advice ?