I understand your confusion.
First of all have you seen the video on the website?
If you right click on it and down load it is larger and you are able to see it better.
To start with you need to put the blue sleeve over the cap and make sure that the vent hole is covered.
Then roll the sleeve up all the way until the entire sleeve is on the cap. This will give you a clear shot to the cap with the head of your penis. (This is very important)
If you are using the yellow cap for protect the head of you penis (I don’t) let me know and I will tell you about that as well.
I like to get a bit of blood in my penis at this point and do a little squeeze by grabbing the mid shaft of my penis and allowing the head to swell.
Place the cap over the head of your penis.
This part is a bit tricky but it is worth it for me. Pull the skin back toward the pubic bone while keeping firm pressure between the cap and the head of your penis. (This will keep the skin from being gathered up when you let the roll down)
Then unroll the blue sleeve until it fall off of the cap and onto your shaft (it should still be over the cap and covering the vent hole)
Now you can let go of everything and relax, the hard part is over.
Gently pull on the cap and grip your penis again mid shaft, push the cap firmly on your penis, with your thumb, push the blue sleeve back to expose the vent hole. You might hear a little psst sound of the air escaping the cap. Let the blue sleeve back to cover the vent hole and pull the cap. Give it a tug, if it feel like you need a better vacuum do it again until you have a good seal.
At this point you are hooked up and ready for a good hang or stretch or whatever.
I like to fold the blue sleeve back on itself up to the cap to allow as much as my penis out of the sleeve as possible. Remember it is not the sleeve that is holding your penis, it is the vacuum.
Experiment with this and let me know how it goes.
I like to have the vent hole facing the underside of my penis as it does not contact the skin that way and you don’t get a little circle on the head of your penis afterward.