You'll need a 7mm allen socket/wrench to remove the caliper slide bolts, then a large pair of pump pliers to compress the caliper piston. All the other tools are basic metric hand tools.
Make sure you clean the pins really good, you'll see that they get some crud on them and that will prevent the caliper from operating smoothly. Lube the pins with high temp silicone grease.
Clean all of the caliper where the pads slide, you will see accumulated brake dust that needs to be removed. Lube all the places where the brake pads contact the caliper with high temp silicone grease.
I recommend the grease and all brake parts are purchased from Volvo to help prevent squeaking later on.