|This is the tab that needs to be pushed|
down on 1973+ Beetles
On 1973 and later models the seats need to be pulled almost all the way back then push down on a tab on the center hump. This tab locks the seat in place so the front driver/passenger doesn't pull the seat all the way out. The seat will then pull back all the way out. (On the earlier seat rails the seats will slide forward and out. There will be a little tab at the front of the seat rail with the lever, push this down and the seat should slide the rest of the way out.) The white plastic bushings then easily snapped in place. I realized I only had one of the 6 bushings needed for both seats that was left. Glad I replaced them.
Two of the bushings were installed on the seats and the third was installed on the center hump. After that I greased the seat rails with some white lithium grease before re installing them. It makes a world of difference and it doesn't cost very much to do either.