Once you have successfully connected your tablet and computer to the same network (whether ad-hoc or router), you can setup MIDI ports. First, make sure the Lemur Daemon is running on your computer. Then, go to the settings in the Lemur app and select Daemon Input/Output 0 in MIDI Target 0. (advanced users can configure several targets, as they please)
If you are using a hardware interface (iRig MIDI, iConnect MIDI, etc), you do not need to use the Lemur Daemon.