Guess this isn't as obvious as I would have thought it was. I am having trouble figuring out how to explain it.
Reverb send is on the Reverb Out
Reverb return is the master on the Reverb Out
Add reverb as needed to the chosen output mix. Usually LR out. (Can also be any chosen Aux outs.)
Generally, effects are normally used post fader.
Cheap mixers usually only have a control on the reverb send. Easier to use, but doesn't give you the entire picture of how it works. There is one more control here than you usually see on internal reverb. But if you had an external reverb unit, it would have all of those controls. Channel send to reverb, Reverb send back to the mixer, Reverb channel to mix on output.
I estimate that the DL1608 has about 700 controls with only 18 on the mixer itself. The 806 would have about half that many.
I'm wondering how your adding music to your mixer? Are you using the ipad channel? There have been people experiencing full volume WHITE NOISE when doing that. It's a small percentage of users, but it's worthy of note. Check other posts in this forum. I'm sure it's not a pleasant experience.