Alright, let's get a bit more productive. Ignition turned off, right foot on the brake, push in the clutch and try moving the stick shift through the pattern, one gear at a time until you get to fifth, then back down again. Now try to find reverse. It is often hard to find. If you've been quiet so far, now might be the time to finally ask the owner something like "How the &*&$% do I get it into reverse?" They will tell you the secret, which depending on the make and model may involve a modified golf or bowling grip.
While you're waiting for changeWhat if you want to go from 35 MPH in 3rd gear down to 20 MPH, and then cruise at 20? Just let your foot off the gas and coast down to 20, or even put your foot on the brake a bit with the clutch still all the way out. OK, I never promised you that the brake / clutch thing was an unbreakable rule, just a good one to start with. So, it is OK to slow down to 20 MPH in 3rd gear and cruise - you don't have to be in second. You won't have as much power to accelerate again while in 3rd, but it will be just fine.
Have you ever been following a car that suddenly slowed down without its brake lights? Chances are that the driver changed to a lower gear and let the clutch out quickly, which made the engine take some of the extra momentum from the car and slowed down without the brakes. You can't use downshifting / engine braking to bring a car to a stop, but you can use it to slow down. Downshifting as you come to a traffic light is particularly useful: as you use the engine to slow you down, you are automatically in the right gear to take off again when the light changes to green.
The next step is going from first gear to second. This is pretty much like when you practiced pushing in the clutch to coast around a corner except that you are going to move the shift lever from first straight down to second while you have the clutch on the floor. Let out the clutch while increasing pressure on the gas pedal just like you did earlier. Practice this on a straight area of course. Once you get into second gear, you can drive around the lot a bit. Remember, take your foot off the gas when you push in the clutch. If you don't, the engine RPM's will go way up without the load from the transmission.