Trying to replace rear brake pads on 2007 kia cerato got old ones off having problems trying to get new ones on

Which belt? You most likely have a pulley not working correctly either it is stuck or the bearing are damaged and jerking it to a stop braking the belts. Another scenario is not being tension correctly or have a bad tensioner

remove caliper bolts, remove old pads, install new pads, tighten caliper bolts, pump brakes until firm.

I had the same problem with my 2007 kia optima. Replaced the pads at about 30k, The pads tend to get stuck and not fully release from the rotor. I took mine to the dealership at around 45k and they replaced the calipers and pads under warranty. According to the dealership the rear brakes are suppose to be serviced every 15k to prevent this from happening

use the bleeder valve to release pressure and push the pads back , look carefully and you will find the screws that hold the housing in place
dont forget to bleed the brakes before testing on the road

One side,turns right,and push in slightly,and the other side turns left,to retract.

First take of the caliper. Once you do that, take off the old pads. To get the piston pushed back, you have to turn the piston clockwise and push it in simataniously.

it has front and rear disc brakes, disc brakes are very simple to change out. Most disc brakes have two bolts that hold them on, one on the bottom one on the top on the inside of the brake caliper, they may be an allen head, or just a bolt. Remove them counter-clockwise. After you remove the two bolts, lift up and away on the caliper and the whole assembly will come off. Once you pull the assembly off you will see the two pads, one of them is driven by a piston, the other one is fixed. Remove the fixed one, they just pop off (have little metal clips you may have to slide the pad off). Take a C-clamp or something comparable to squeeze with, place it on the back of the caliper and on the old pad thereby squeezing the cylinder back into the piston, once you squeeze the cylinder back into the piston, it will give you room needed for thicker new brake pads. Piston should retract with the c-clamp fairly easy, shouldn't be a whole lot of resistance. Remove c-clamp after you get it to retract and remove old pad. Put new pad on, just like you took the old ones off. All four are basically the same to change out, they all have two bolts holding them on. You pull those, get the pistons to retract and replace the worn pads, put them back on, line up holes, put bolts back in... and your good to go. When you get back in the car and turn the key on, you may have to pump the brakes a few times.

If your rotors are good and fairly smooth, then a decent ceramic pad will work well. Just be aware that ceramic pads will require a slightly greater paddle pressure. They will last longer, dust up a bit less and will perform MUCH greater in stop and go traffic...

I suspect that 25 dollars per axle is a typical cost for good quality disc brake pads.
-Jim

make sure you have the piston compressed all the way and the adjuster compressed all the way, if so check the thicknesses of the new pads and or rotors if they were replaced you may have a clearance problem that requires a little machining

all brake pads should be free from rotor until pedal is depressed.