You should just collect all your trimmings from harvest and place in a freezer bag.
Place in the freezer with all the air pressed out of the bag.
Let freeze for aprox 4 hours.
Then you can shake the clippins over a silk screen stretched over a wooden frame.
Once you have shook all the trichomes off of the weed clippings then scrape the kief/dust up and place in several layers of wax paper and then use a clothes iron to press.
That is just off of the top of my head.
I am sure it should be more detailed but, I did not feel like it.