They make it seem so tough just so people won't mess it up. Essentially, heat the herb in a double boiler to dissolve the THC (the solute) into either alcohol or fat (solvents). Some common solvents could be olive oil, tequila, everclear, vodka, or butter. Then strain it out. Coffee filters are convenient for sure, but the wicking effect of paper filters will cause you to lose some of the precious THC, so if you can find a fine wire mesh strainer, that would work much better. Also, remember if you're using butter, that it can be re-cast into sticks, chilled, and used just like the stick of butter it once was (though now enhanced!).
So in short you only need a source of heat, cannabis, and an alcoholic or fatty substance, and a filter.