On the most basic level its not hard at all. I am going to give you some steps here that Matt Rize would dissagree with and I will be the first to say that his method and finished product are better. I will be using his method in the future because the pics of his finished product are straight up cartoonish.
Here is the "basic, dumbed down version" for you. If you are not concerned about how much they cost get the name brand "bubble bags" or the ones that I have are called "Drop Bags" if you want to do this on the cheap just to see if its something that you want to do more of you can get these cheap as$ e-bay ones..
CLICK HERE I have not used them and I am of the belief that you get what you pay for so they mighy only last you a few times but for under $30 with free shipping go for it. On that e-bay set you are going to have to work the hell out of the 25 micron bag since the one before is 100 mic but if you have more time than money its your trade off.
The next thing you need to get is something to mix the "mash" with I use one of these
CLICK HERE instead of the paddle type because it beats the bud less and less plant matter gets ground up. You will obvously need a drill to use it but I will assume you have one or have access to one.
You will also need 2, 5 gallon buckets.
Stack the 3 bags in one of the buckets with the lowest number at the bottom then the middle number and then the largest number.
in the other bucket put a bunch of ice in the bottom (like 3 inches worth) then a few inches of trim, then a few inches of ice then more trim and more ice. You dont want the bucket more than half full. then pour cold water into the bucket to wet the whole thing down. Just enough so you can see the water.
Let sit for 10-15 minutes.
using that big bit on the drill start mixing the mash up. you dont want it to turn too fast so make sure the drill is on the screw setting and keep hitting the trigger off and on. You want it to be more of a washing machine action than a whirlpool action. do tyhis for 10 minutes.
Let sit for 5 minutes.
pour that stuff into the other bucket with the bags in it.
now shake the top bag as you lift it up. Its going to have a bunch of ice and trim in it but shake the hell out of it so most of it drains.
Now take that bag and set it in the now empty bucket that you were mixing in because you will be able to rinse it again later and do another run.
now grab the 2nd bag and slowly lift it up using a gold mining type action. Back and forth until there isnt much water left in it. Keep doing that until there is a "lump" in the middle you can scoop out with a soup spoon.
scoop that shit out and drop it on a cookie sheet to dry.
Do the same with the last bag.
scoop that shit on a cookie sheet to dry.
dump the water thats left in the garden.
pour a bunch of ice water into the 200 micron (work) bag that has your trim and ice in it and shake the shit out of it. and lift it out doing that gold panning motion and get rid of it.
in the empty bucket set up your 25 micron and 100 micron bags again and dump the water into those. Now do those like you did last time and put the stuff on your cookie sheet.
You can put the cookie sheet under a lightbulb to help dry it but its going to take a few days to dry out.
search Bubble hash on you tube and you will see people working the bag like a gold pan to see the technique.
Not the best way but easy, cheap and it will get you high!