You will need help of a carpenter, because a wall drilling machine is required here. Figure out where this shelf will be most suitable for your cats and follow the installation steps.
Step 1: Drill holes in the wall as per the holes given in C-shape wooden unit
Step 2: Put screw holders (plastic) in the holes by hammering them inside the drilled holes
Step 3: Attach the C-shape wooden unit with screws given in the kit
Step 4: Put on the shelf on the C-shape unit and screw it on the given holes
Ensure the C-shape unit and shelf both are tightly placed