Hi Martin, well. Open Biab, put all the chords in the at you need for the tune you are working on. Select a ready made style that puts you near to where you want to be, Swing ballad latin etc. You may as well generate the tune and listen to what it sounds like..
Right, for the next step, click on the individual tracks you can start with the Bass track on the far left, get yourself to the main RT menu. From there if you have loads of RT's go to the bottom of the page and type Bass into the filter box then press apply. The only tracks now shown should be Bass tracks. Select one that is correct in tempo and feel, ( tempo is OK+-25bpm) If you have an up todate version the far right hand column could have an 's' showing that is for a simpler version, also top RH side of the menu you should have depending on which version 3 more check boxes one for tempo, bluesy and simple. You can check one if you want..
Do something similar for each track that will create your own style. Now you can save all these but I find it better just doing it on the fly and trying to be creative with them. Also most RT's have A and B section substyles which you need to be aware of. Hope this points you in the right general direction..