Ok, you sound like you're new to the hobby. It's not all that complicated. Your Steering servo wire goes into Channel 1. Your Throttle servo plugs into Ch. 2, and if you have a 3rd servo or accessory, it'll go into Ch. 3 on your receiver.

Just go back to your stock radio, turn it on. Plug your old receiver back into the truck like I advised above, and turn it on. Don't run your truck's engine, obviously. Now test your trigger, and steering and make sure the correct servo moves.

If it's too confusing, plug the steering servo by itself into the receiver's slots, and test your steering to see if it works when you turn the radio's wheel. If the servo is plugged into the correct slot (channel) on the receiver, it should steer. Leave the steering plugged in and move onto the throttle servo, and test it with the trigger to make sure it works in the correct slot. So on and so forth.

Let this be a lesson. Don't just blindly pull wires out without understanding where they go first. And if you are upgrading to a DX radio, at least know what the wires plug into and what they do.

Most likely assuming all your equipment uses 3 wire servo plugs, your connectors need to be trimmed a little to allow them to slip into the new receiver's slots.