Mixet Shower Faucet

Where can I find a manual on how to adjust this. My problem is I can't get the Temp handle to sync. with the flow valve

There's manuals? Geez, I've been doing it the hard way.

NOT! But what do you mean by not "sync" on the handles? Mixet is long out of business, so there is no support, but parts are still available.

You and ten million others have a problem with Mixet. You will need to change out the cartridge and any other bad parts, or, better yet, replace the entire shower manifold with a Delta or Moen.

Sync? The temp handle should turn independently of the flow control knob. If the temp handle turns a full circle, perhaps someone who worked on it lost or left out a "key" that should act as a stop. You might find packaging on a new stem part that has a diagram and some brief instructions.
In any case, don't expect good temperature control from these Mixet valves. Experiment with settings in hope of finding a good temperature.

Mixet

Only the "old" long pattern stem had the stop "C" clip, and it is usually thrown away when the stem is replaced because it serves no useful function. As far as syncing the temperature and flow, we would have to know what you mean by that. The instructions for the valve are;
1. Turn on the water to the desired flow.
2. Turn the temperature lever to the desired temperature.

Those are the only instructions needed for that valve.