Now that the pad is tied to your skate, bring the pad to an upright position on top of your skate and attach straps of the knee protector around your leg.
As I mentionned previously, the knee protectors on pads are usually inadequate. As you can see in the following picture, there is a gap near the attachment of the knee protector to the pad (on either side). This area is certainly large enough for a puck to make direct contact with your knee. This is why I highly recommend knee pads unless you have an extremely good knee protector on your pad. Your knee protector should also go under your pants to ensure you have better flexibility (unless you have thigh boards).
Once your knee is properly secured, begin attaching your straps. The top two are usually simple buckles that require no adjustments. The first few times you wear the pads, adjust the length of these straps so you are comfortable both standing and when in a butterfly. They should not be so tight that they stop your circulation when your knee is bent, but also not so loose so the pad does not follow your leg. For the other buckles, tighten them to your liking but ensure you always have them at the same length from game to game (after your adjustment period). If you change the tightness of your straps, your pads will be positionned differently when you are in a butterfly/half butterfly. Small details like this can mean you let in goals or you are not comfortable while playing.
TIP--> I personally count the number of holes in the strap to know which one is my regular position (I use 4, 6, 8, 8). If you don't want to count, you can also mark the strap with a permanent marker.
TIP--> Don't tighten your straps too tightly, your pads are meant to move to be properly positionned when you are in a butterfly. (I like mine tight as this was the style before pads were built for the butterfly style, but I also have developped the flexibility to use them that way throughout the years) If you are just starting out, try to get them fairly loose, especially towards the top of the pad.