I don't have a guide but I'll explain it best I can.
Build a wood box that will contain your filter. Make the box JUST bigger than the filter. Screw the box together, then use a construction adhesive such as "pl premium" on the inside joints of the box, this will provide an air seal as well as some strength for the box.
Leave one end of the box open to allow you to insert the filter. You will later make a hole in this last piece of wood that will allow you to hook the fan either directly to the filter OR attach a pipe or hose which will then connect to your fan drawing air through the filter. For the fan to draw air, we now need to cut a hole in the side of the box that will allow you to attach a hose that comes from the inside of your tent.
Air will be pulled from inside your tent, going through the hose attached to the intake hole in the box, this air will then be drawn through the charcoal filter exhausting out the top of the box.
You want to have this system as air tight as possible. I used a rubber foam type door seal for the lid section with the exhaust hole, screwed down and I even taped it for overkill.
Think of the box as a mini air tight tent, it's drawing the bad air from your tent, exhausting it out the top. Maintaining a negative pressure in your tent while keeping it out of your tent.
I found using HVAC attachments worked best for the intake port, allowing me to keep it airtight. Airtight is crucial for this to work well.
Good luck and i hope this helps you. I'll do my best to help. If you have any more questions, shoot.