how to set trim, pre-amp level, in DEVA 5.8 recorder on location for condensor and lapel mikes?
You can do two things. There is a "fader assign" menu that let's you map the front knobs to the individual channel strips (you can even assign multiple channels to one knob, which is a nice feature if you're doing things like stereo recording). The knobs can be configured to control both input and output faders. Just make sure you keep track of how you set them. For the second option, you can also assign the touch screen to display the faders for the channels.
A related item for you is the trim control in the individual channel setups (where you activate 48v phantom power). There is a fader on that screen that adjusts the overall gain range for that channel, though it's meant to be set and left alone for the remainder of the shoot. You should use the faders to control record.