Oh... these machines don't do that. We usually just plan a good route to the bottom.
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All kidding aside.... pull both on BOTH sticks to stop the vehicle completely, or to hold it on a hill. One very important note is that the machine MUST be in gear in order for the laterals to hold it on a hill. If you shift in into neutral, the sticks are useless, and THEN you really need a good route to the bottom.
So ... ahem... let's summarize.
gear selector in forward: Pressure on both sticks to go forward, relieve pressure on left stick to turn left slowly, pull back firmly to BRAKE the left side to turn left quickly. Vise-Versa for right hand turns.
gear selector in reverse: Pressure on both sticks toward you (pull backwards) to go in the reverse direction. Relieve pressure on either stick to turn in either direction slowly, or push the stick all way forward on either side to make a more rapid reverse-turn.
The T-20 transmissions have a ton of breaking surface on the drums, so it's a pretty efficient brake. You'll get used to it pretty quickly once you spend some time behind the sticks. The tricky part comes when you're bouncing around at 30mph or so...
You'll get the hang of it....