hmmm I take it your new to fl.
well first you get your midi file and open it with fruity l00pz and then the import midi data dialog box will come up uncheck the create one channel per track then click ok or the tick or what ever button they have to exeicute the command.
step 2: right click on any of the channels and goto insert channel then click simsynth

or any one of those you have installed.
step 3: you see the channels on the step sequencer well theres a little light you click on to high light the channel you want to work with. click on the first channel and then go up to edit and cut. then high light the simsynth channel then goto edit and then paste now play the patten if you hear some sound you did it right
then so on for the rest of the pattens put new channels in for each patten
Any time bro I should start a Fl forum im new here since yesterday been using all kinds of hardware and software to makes music for 4 years