If you are making biochar, I highly recommend the pit method - much more bang for your buck and the only high tech bit is a spade/shovel for digging the hole and then collecting your biochar once it has cooled. You do need a good way of quenching the fire once you are finished loading - either (a lot of) water or possibly a sheet of roofing iron or similar to cut off the air (some sand/earth around the edges to seal it)
Steven the SkillCult guy has a good video on this method
https://www.youtube.com/watch?v=I1jAo7qd_Q8
If you want higher quality charcoal, I'd recommend filling the 55 gallon barrel fitting the lid, and then ensure there are a few holes punched in one side. The holed side faces down in (again) a fire pit - and when it gets hot enough the escaping gases will add fuel to the fire. Once that process stops your charcoal is done.
