I have the 20B so can only explain on the app (same for Android and iOS). Lower left hand side has the ins/outs selections. Third one down is ST. IN/FX. I have ST1, ST2, USB, BT, and 4 FX strips. The BT is the Bluetooth one. It defaults to a Quick 3 channel EQ but you can set it up to be a Complete strip if you want.