I have gone more than 12 years in the building trade without even attempting a mortice and tenon joint. Watch the video, it shows me trying it. I do a tenon with a fox wedge thingy to hold it into the mortice.
Have a look at an old timber door if you have one, it is likely to be made out of a series of timber pieces connected by mortice and tenon joints. You can tell by looking at the edge of the door, there will be a bit of end grain showing.
Some of the doors we have been removing have been bigger than a sheet of ply. Huge doors all held together without nails or screws
|That guy is 6″1|