1. Remove the litle black rings from he bolts on your head tube with a screw driver.
2. take out all the parts used to fold your scooter. Axels bolts Knobs Etc.
3. Take of your Headtube which is attached to your bars and fork and clean out the inside so there is nothing in the head tube.
4. Place the Head tube on the deck so the holes line up with the foldy
5.Put two 2 and 5/16 sized bolts wheres the hols line up with the fold.
6.Tighten all the bolts Hard core.
This is asuming you have a new a. if you have a old a or a pro u can put a extra 2 3/8 bolt behind the headtube to reinforce it.
Edit: sorry bout the double post.
There is a video guide in the mod sticky thread. but if you are a person that needs to read things there yo go