This depends, like most things, on how much you practice. It could take anywhere from thirty minutes to a few hours to get the basics down. From there, you just need time behind the wheel to learn how not to stall and how to be smooth with the clutch pedal, something you’ll have to get used to on every manual vehicle, as each has a different feel.
If you drive every day, it shouldn’t take more than a week or two to feel completely confident in your new skills driving a stick shift vehicle.