It seems daunting at first, but it is quite easy once you've done it once or twice and understand what's going on.
Basically here's what you need to do
-Obtain a solvent that will dissolve THC, and can be fully purged out at the end (since you don't want to be consuming the solvent)
-Put the solvent and the THC in contact for long enough that the solvent can dissolve the THC
-Filter this solvent/oil mixture to remove any plant matter
-Remove all solvent from mixture.
two of the more common solvents are ISO, and Butane
For your first run, get absolutely everything ready beforehand, have it out, on the bench, and do a mental dry run.
Just sorta get a feel for where all your materials are, and how you're going to use them, you don't want to be stressing that you can't find something while you are dealing with volatile chemicals.
I'll try to do a step by step breakdown
STEP 0 - SAFETY
ensure everything is safe for the extraction. This means NO FLAMES.
If you're a smoker, have a cig before your extraction and then wait till you are completely finished, avoid anything that could spark or just generally set a flammable gas ablaze.
STEP 1 - PREPARATION
Get your extraction vessel (a mason jar is usually the easiest to obtain for this kind of job).
Line it with cheesecloth or something similar. Something that will allow you to remove the majority of your herb from the solvent quickly and easily before you filter it.
Get a 2nd mason jar, and secure a non-bleached, brown paper coffee filter to the mouth.
Ensure your evaporation dish is clean, and dry. If you haven't used it before, run a razor along it to see if you will be easily able to scrape up the thin layer of oil. (I once bought a dish that had a very slight curve along the sides that made it very hard to scrape up)
Prepare your double boiler setup at this point if you plan on using one
STEP 2 - EXTRACTION
Place your herb (somewhat broken up, but not necessarily ground) into your cheesecloth lined mason jar.
Add enough ISO to just submerge them.
(Some people freeze their buds and isobeforehand, which can lead to a purer product at the end)
Let the buds soak for 1-2 minutes, I usually give them a bit of a shake during this time, (but that is optional).
Pull the buds out along with the cheesecloth, and squeeze the excess ISO out back into your mason jar.
At this point your ISO should be a golden brown/yellow, with a few small bits of particulate in there, with maybe some dusty looking stuff on the bottom of the jar.
Pour your ISO mixture into the coffee filter in the 2nd mason jar.
This will remove any of those particulates
The ISO should now be that golden brown/yellow, with no particulates suspended in it.
STEP 3 - PURGE
pour your nice filtered ISO mixture into your evap dish, and either let it evaporate off naturally, or use a doubl boiler setup (IMPORTANT NOTE - NO FLAMES URING PURGING, also if you're using a double boiler, it would probably be inside, so make sure there is lots and lots and lots of ventilation)
Eventually, all of your oil will be left in the pan, and all of the alcohol will have evaporated away.
Then you just scrape it up and enjoy