Here’s a step-by-step:

Breathe normally throughout the exercise to prevent yourself from suffocating. Also make sure your heart is beating normally.
Grip your pen in your good hand. That is, the hand you write with. Make sure the tip is extended and it has proper ink.
Press the pen to your paper. Make sure it writes, maybe do a squiggle to be sure.
Look away and don’t look back. At no point lift the pen from the paper. Stare at your other hand.
Start by looking at the point where your wrist meets your hand.
From there, let your eyes follow the contour of your hand (contour being the edge, or any lines you see).
At the same time move your writing hand to match what your eyes are seeing. You’re drawing lines, here.
Remember not to peek at your drawing at any point in this exercise.
Keep going. when you reach a knuckle, follow the lines of the knuckle as they zigzag across your finger. Then return to the edge of your finger, and go on.
Similarly when you reach a nail, follow the line of the nail. Notice that there’s several lines in your nail, the crescent of white at the edge, the big pink part, and another paler part near the base. Follow the lines of all of these.
Remember not to try and do any shading or color anything in. You’re just following the lines.
Once you’ve drawn all five fingers, and you’ve reached the other side of your wrist, you’re done! You can look!

Don’t worry if it looks like crap, it’s supposed to. You win the day. Here is your prize, your hand picture which you can crumple up and throw away if you want, or save for ever and always and such because it’s your first drawing as an artist.