Welcome, Please work with me to get the answers you need.
The brake pads are held by three pins and a pin locking spring. First, you pry up the plastic cover over the brake pads. You can check the condition of the brake pads at this point.
There are two larger pins near the edge of the pads and one smaller one in the middle. You can drive one of the larger pins out from the backside and then remove the other pins and spring. Before you remove the old pads you can pry the pad piston back to make room for the new thicker pads. When you push the brake pistons back into the caliper the fluid level will rise in your fluid reservoir so watch it doesn't get too full and run over onto your bike or paint.
Put the new pads in place with the friction material facing the brake disk. Keep the pads clean. Put one larger pin in with one end of the spring attached. Put the small pin in and push the spring down so it hooks under the third larger pin. The spring will fit over a groove in the smaller pins center area. The spring pressure holds all the pins in place.
Replace the plastic brake cover.
Never pull the brake lever when the pads are out or your pistons will go flying, big mess.
Try your brakes gently a few times to make sure they work and the wheel is turning okay. Use the new pads gently but firmly to break them in. That's about it! ----------------------------------------