You need One of these blocks
It goes in where the purple arrow is, and as you can see it has a small nub that rides in the yellow track. When you twist it moves back. Lastly you need the screw that goes into the slider block. It will be instituted into the block to pinch the cable where the orange arrow is. The white arrow is your cable adjuster
For install of a new cable.
With it disassembled, clean all components. Throttle tube, slider block, and all screws. Also clean the track where the block gets inserted on the actual handlebar piece. Use a tooth brush and carb cleaner.
Use some spray lube like PB Blaster, or other oil on the throttle tube, slider block, and spray some in where the slider block gets inserted.
The slider block has a set of threaded holes where you run a bolt through to pinch the cable. This end goes into the channel FIRST.
Put the slide block on the throttle tube, with the diagonal oval nub resting in the curved channel. Make sure the slider block is in the correct orientation with the threaded holes further away from the grip. Insert the slider block and throttle tube into the main throttle assembly.
Tighten down small set screw in the hole on top of the main throttle assembly make sure it is in correct the throttle should turn free and easy, but should not be able to be pulled out.
From here it’s easier to adjust the whole throttle so you can see the long oval passage on the under side of the throttle assembly. You should see the small slider block inside and the threaded hole for your pinch bolt. Roll the throttle the whole way FORWARD (off) so the slider block is all the way at the front (furthest from the grip) it can go
I always start with the throttle cable already hooked up the the carb good to go. Make sure your adjuster is in the whole way, and insert a raw cable end (no Knarp or block on the end, you may have to cut one off if the cable you bought has something in both ends) into the adjuster. It helps to have a good 4-5 inches of cable outside of the housing and and finagle it through the slider block. You should be able to push the cable until you can see it where you put the slider block in initially. Gently grab it with some needle nose pliers. And pull taught.
Now, use your cable adjusters to take any slack out of the cable housing, it’s best to do a little on each one rather than max one out and have one untouched.
Now, grab the throttle and rock it all the war forward (off) and hold it there, grab the extra cable hanging out from where you pulled it through. Pull on it you should feel the carb slide raise and you should hear/ feel it shut when you real estate tension. Give it a few good tugs to make sure everything feels smooth. Return it back gently and insert the pinch bolt/ screw and tighten.
Then pull the throttle and make sure the slide opens the whole way by looking into your carb or feeling with a finger. You may have to play with the adjusters again a little bit. But make sure it’s not too tight (it will lift your slide causing a super high idle, might even pull out from under you) If everything is cherry pull the throttle the whole way BACK (full gas) and trim whatever cable is hanging out.