The problem is, I'm pretty clueless as to when/how to wash them.
Wear them for as long as you want, really. I advise washing them as soon as they feel unclean.
I've read about people waiting for months before the first wash, is this pretty standard?
People do this because it creates a sort of contrast on the denim if you delay the washing. However, it is only really noticeable on denim where the indigo has not already been washed and blasted and sandpapered, namely, really dark (almost black) jeans. I am assuming that your Diesel jeans have already undergone some treatment. Do they have whiskers and fading on them alredy? If so, there's no sense in waiting extreme amounts of time to wash them.
And what about subsequent washes?
Same rule as above. Wash 'em when they feel like they need a wash. Can be after one wearing or after ten.
Also can I just toss em in a regular load of laundry or is there some special method to it?
To keep them looking nice and the color closest to its original state, it's best to wash them only with other jeans, and a detergent that doesn't have bleach (or a bleach alternative) in it. Woolite Dark is my preference. You can also use a vegetable-based castille soap, such as Dr. Bronner's, which is truly mild. A cold wash is mandatory, and it's best to hang dry them instead of throwing them in the dryer.