hi can anyone please help me i cant fit the new brake pads there is not space and cant push back the parts

Firstly I assume that you've got the correct pads, same shape and size as the old ones, just a lot thicker.

The caliper piston needs to be pushed back in carefully. Any offset pressure can cause it to tilt slightly and jam. However, replacing the most worn pads and pressing the brake pedal will usually unstick it again. If you need to lever it, use a bit of wood across the piston to spread the pressure and prevent damage. Can be done with a G-clamp, but again take care to keep pressure even.

As you push the piston back, fluid will be pushed back up the pipes to the reservoir. Be careful that this does not overflow onto the paintwork, as it is a good paint stripper.
One trick is to open the bleed nipple when pushing the piston back.