Here you can set-up sound blaster emulation. Select a type of sound blaster and configure the IRQ's and DMA's. The defaults usually work just fine. You can't really go wrong here. The only reason to change anything here is that a game only supports a Sound Blaster Pro 1 and not the Sound Blaster 16. Or a game might prefer a certain IRQ or DMA. In that case you can change as much as you want.
A final note. OPLMODE is best left on AUTO it's the default for a very good reason. The thing is that the OPLMODE is dependant on the sound blaster type. However, if, for some reason you want to combine OPL3 with a sound blaster 8 bit. Go ahead but it's NOT natural to do so because the actual hardware never supported this.