There is a preferred way (orientation) to attach your telescope tube to the mount.
First place the mount on the tripod and position it so that the altitude clamp assembly is to your left. Loosen the altitude lock and turn the clamp assembly so that the mounting bolt is on top and the dovetail clamp is level.
Next, lift the tube with its front (for the reflector, the end with the eyepiece holder and StarPointer, for the refractors the lens end) in your left hand and the rear end (mirror with Celestron logo for reflectors, eyepiece and StarPointer end for refractors)) in your right hand. Slip the bar on the tube into the clamp. Be sure it’s all the way into the clamp. Center the bar in the clamp. Finally, tighten the clamp by turning the knob.
Carefully turn the altitude lock to tighten it. Be careful not to over tighten the altitude lock.
Visually confirm that the bar is centered and firmly seated before letting go of the tube.