The handlebar has a groove, firstly a small block is inserted which hold the throttle cable. The nipple on the cable fits into the slider as you can easily see.The throttle tube has a welded-in steel-plate "worm". The aluminium end piece holds the assembly in place. When everything is connected properly you can imagine that the throttle choke is pulled open, but also pushed back into the carburetor(s).

Yamaha early throttle slide components