hello, can someone tell me how to plug headphones on my delta 2496 ?

Go to radio shack and get an adapter (or adapters) that take a single mini-plug stereo female and converts it to two 1/4 inch mono balanced or unbalanced male connectors. Plug the male connectors into the 2496 and the headphones into the female end.

Note that if your headphones are stereo 1/4 inch then you will need a 1/4 inch stereo female adapter and not a mini-plug.