Sorry for taking so long getting back to you, I have a major cold.
and I hve spent the weekend in bed watching football.
So I am not sure if you are using a head phone preamp for the head sets so if you are you will need a quater inch cable to RCA
pluged into the studio outputs on the top of the board, then you need to press the shift key then the Moniter key #6, on the right side of this page you will see studio setup this allows you to deside what the listener with the head set hears, so if you are doing a sub mix for the musician normally using AUX 1+2, then press the circle next to 1+2 that way when your on the board switching between control room select buttons to listen to your recording mix and switching to the sub mix the user with the head set will only hear the sub mix. also the T/B level nob on the top of the board will need to be adjusted for volume.
also after pressing the monitor key on the left side you will see control room select, you should probably set the select 1 key to AUX 1+2) and the select 3 key to (2 track analog) this way if your recording using a sub mix you can switch between select Aux 1+2 and and Main mix and then also you can bring your cd recorder or something into the RCA 2 track in's on the top of the board.
Now if you are just planing on using the phone jacks at the top of the board and thats what you want to use the talk back button for this is a bit differant.
The only way I know of to do this is by using the (to Slate button)
on the top of the board. First press the shift key then Moniter key
under studio setup press the circle next to control room, then press the OSC/COM button then press Int-Tb mic and or if your using Aux 1+2 then also press Aux 1+2 and ST-LR, Remember to set the T/B volume level nob on the top of the board for your talk back level. the To Slate button will be your talk back button.
If you dont have a head phone preamp there pretty inexpensive.
the Sampson Q5 is under $150 and the Behringer ones are under
$100, only if you feel you need it other wise the slate option should work just fine.
I will get back to you on your Effects question. I hope this info is written so you can figure it out. I will check in to see if you need better info.
Good luck