concept and application - a few minutes in a parking lot or some very dead roads
doing it well - varies from person to person - practice makes perfect
I had driven friends cars - so I knew what to do. But when I bought my first manual (85 Jeep Cherokee), I test drove it with no problems. Bought it, took it to a gas station - filled the tank, and spent the next 20 minutes trying to get into first without stalling. First week was a little rough, I'd make stupid mistakes like forgetting to downshift in a parking lot and stalling from leaving it in 3rd or 4th.
Ultimately, just keep the radio off and pay attention to what the engine is doing. When in doubt, more clutch, less gas - the goal is to be smooth. Anyone can tach it up and slip/dump the clutch, but driving stick smooth is arguably what the goal should be.