Help with basics of PC SCROGING?

Im setting up pc case for a plany i have for cfl's across the top a fan to bring air in and a fan to take air out i dont have much room for growing so ima scrog but dont know how to do it.

I was told that you make a screen and train the plant to grow underneath the screen.

You would train the plant underneath the screen during its Veg cycle and flower cycle.

Let the plant shutes grow through the screen holes about 2" to 3" above the screen then pull the shutes back down through the screen.

You keep training the plant until the plant has stop growing. Once the plant stops growing vertically you let the shutes grow through the screen holes and stop training the plant.

how do you train the plant??? .... this is my first time growing

I have not done scrog so its pretty much the blind leading the blind.

You pull the shutes under the screen hole and force the shutes to go horizontally by tieing it to the screen, the shutes will grow back through the screen, let it grow for about 2" above the screen then weave it back through the screen hole and use ties to force the shutes to go horizontally.
You do this until the plant stops growing vertically.

If its your first time growing you should do a search and read up on scrog and maybe read up on growing in general.