i'm new to grinding my own coffee beans. how long do i grind for a regular coffee machine?!

Because coffee grinders are so different it's hard to estimate an actual time interval. If you're used to buying ground coffee, eyeball it until the consistency looks the same as what you were buying before. I usually start with two or three short bursts followed by a few seconds of holding down the button until it looks right. You'll get the hang of it through trial and error.

Blade 'grinders' are the least consistent way of pulverizing beans: it doesn't grind, it breaks beans into big chunks, small chunks, and powder. This creates more bitterness from over extraction.

If you want a reliable way to produce a delicious cup/pot every time, get a decent burr grinder.

I use my blade machine for spices only. If you're going to use it for coffee, do it in 1-2 second bursts to prevent friction from creating enough heat to burn the beans as it chops.

It really depends on how you plan to brew it. For french press you want it to be coarse. If your using a cone filter, you'll want it fine. For a flat bottom filter, you'll want in in the middle.
If you grind it too fine for your brewing process, it will be bitter. The grind really is the science behind good coffee. After the roast of course.

I grind 8 times in 1 second intervals