If you have the back off of the laptop and the battery disabled and have the two fans open to you. Take a picture of how the wiring is or several pictures for reference.
The fans are attached to a het sink tubes and there are 4 screws in the center that hold the center heat sink on the processor. Loosen them completely although they may stay with the heat sink. Now on both fans follow the outline of the cages and loosen the screws around the outside of the fan unit. Again the screws may stay with the unit. now start lifting the fans unit away from the computer and as you encounter wiring carefully unhook the leads as needed. Careful soft movements with a small hard plastic device or flat blade screwdriver can aid in this. Steady and careful is the plan. As you bring the fan units off the motherboard you may encounter a screw not loose so carefully lift and unwire and loosen screws.
The replacement part can come as a complete unit or just fans. The fans are held in the unit by three screws and stick glue substance some times , pry carefully the fans out off the copper heat sink and reverse the procedure for the replacement. You are going to replace the thermal compound on the heat sink over the processor so use a paper towel to wipe and dig off the old material Shine up both surfaces and apply a small dab of compound smearing it all over with a tooth pick or similar. Return the heat sink on top of the processor and squirm it around a bit then have a look to see if your coverage is good. No more than a light amount is needed.
Replay your screws back in and do them a bit at a time round and round so as not to bend the heat sink in one spot. same over the processor. Don't be too aggressive in tight but check them all for about the same light torque. you now have to plug back in the wiring. So if needed you have the pictures you took to remodel it the same.
Now you have been reading this, type in your make and model number and add replace cooling fan for more instructions and video's. Being slow and patient is the key and touch the frame of the computer before starting to discharge any of your static.