Sure, its not really that hard, of course there are several way of making it this is the inexpensive version.
First of all hash is the just the trichomes off of the plant compressed into cookies or bars. So unless you're growing its not really cost effective.
If you grow you can use the trim left over after you manicure your buds, really any part of the plant that has trichs can be used.
Get a coffee filter (the nylon and plastic kind not the paper) or any really small pore nylon screen and take the weed you intend to use and dry it COMPETELY put it in the screen and shake over a piece of glass (I use a cassarole dish) Some folks put some coins or ball bearings to agitate it, what you'll end up with is a pile of white or slightly green dust (this is called kif or kiff).
Now get some parchment paper some folks use a garlic press and put your kiff on the parchment paper fold it so its in a pile in a little parchment envelope and then press between books or rocks or what ever, sometimes you'll have to add heat to get it to stay together (some folks use an iron)
and bingo you got hash.
Other methods involve ice and expensive bubbler bags. One method I saw on 60 minutes back in the 70's it showed some toothless old men in Afganistan, they would take these huge buds and rub them between their palms until they had a this sticky goo and then they'd scrape it off and grab another bud when they were finished the had this big black ball of tar, supposed to be some of the best hash produced.
I know one guy who always cleaned his weed over his kiff jar so any trichs that fall are collected.
Hope this answers your question. I'll try to find the thread that shows pics and post it tomorrow. NH
REALITY is only a concept for people who can't handle DRUGS