Well, there are several methods but they are all a decent amount of work.

The safest, both to produce and to smoke, is called full-melt bubble hash. It's produced without any flammable/toxic solvents, unlike the other methods.

You can purchase a set of "bubble bags" which are basically a series of screens that gradually decreases in size. You'd need two buckets (size will be determined by the bags you buy), the bubble bags, some trim, and a mixer (or spoon, if you don't mind stirring for a long time).

Fill one bucket up with about 3/4s water, and top it off with ice. Starting with the smallest micron size and progressing so that the largest will be on top, place all of the bags into the dry bucket. All hash is best made cold, so toss yer trim into the freezer for a couple of hours before starting as well.

Now pour ice cold water from your bucket into the bag-bucket until the water level reaches above the top-most bag. Having the bags submersed before adding the trim will prevent any plant matter from falling into the lower screens before you begin, resulting in a cleaner end product. Add Trim.

Dump some more ice on top of the trim. The cold will cause the resin on the plant to harden and make it easier to remove via agitation. After you've got a glacial coating on top of your bucket, begin to mix. If using an electrical mixer be sure to keep it well above the water to avoid electric shock. Would mix for more than 10 minutes.

After mixing allow the bucket to sit for an additional fifteen minutes so that the trichs have time to settle down into the bucket instead of floating at the top. Once the mixture has settled, remove your topmost bag from the bucket. This will pull the majority of your trim out with it. Allow it to drain back into your bag-bucket, but do not squeeze.

Let the remaining bags settle for another ~20 minutes. Pull the next bag, let it drain, do not squeeze. This screen often contains a granular green paste comprised of small leaf, which can be used for cooking or discarded.

Do the same for your third bag, contents of this bag may be usable. If blond, place the bag into a large salad bowl and then pull the sides of the bag down around the bottom of the bowl so that the screen is stretched across the bowl like the skin of a drum. A spoon should suffice to remove the glands from the screen. Then rinse your spoon and bag 3 in your bag-bucket to return any glands you were unable to collect that try.

Cleaning bag 3 should have given bag 4 enough time to settle so move right along. Bags 5-6 are where the majority of your highest quality concentrate will come from but 4-6 can all catch it depending on the strain of plant as they produce different sized glands. Glands from bag 7 are usually not included in final product.

After extraction glands are placed onto one half of a pressing screen, the screen is place on one half of a towel, and both are folded over together to simultaneously dry it out and press it into a solid.