Recording a Cajon can be a bit of a challenge in the typical home studio space - I speak from personal experience on this.

Room acoustics can be a boon or a major frustration here. Where the cajon is in the room, where the hole is pointing and where you place a mic (try to keep it simple with a single mic at first) really needs either:

1. two people, one to play and one to crawl around the room listening for where the boom and crack can be picked up at one location.

2. 1 person, but with isolating earphones and earmuffs over top of the earphones that can also rove a microphone and listen while playing. I know where you can get great isolating earphones (PM me) and I recommend the 3M X5A earmuffs for this purpose - this allows you to hear what the mic hears with minimal sound transmission from the room through the muffs and phones.