Welcome to the forum.
It would help to know what you have attempted so far and what kind of problem you are having. Make sure the transmission torque converter is turned clockwise and pushed back at the same time and you will feel up to 3 steps, I always thought it was two steps but others have said three steps, as you turn it and push in. Sets it in to the front pump. Should be dowels at back of block to help align. Have you looked at you tube? Straight in mating and lever as can and helps to have a transmission jack and an engine that is supported by more than two motor mounts. lots of experienced help is also required. Keep the loose lines and hoses and wires out of the way. When mated, pull the torque converter up to the flexplate and make sure to attach with correct bolts.
Others here will chime in with info.