I found floating tenons are the easiest to install on the wide panels
The rational was to build an inexpensive elegant twin bed for my five years old son from quality pine about $150 with the hardware and finish. It took about eight 8 foot boards with some leftover boards for the mattress supporters. The posts are three boards glued together. I used two boards for them. Everything else is pretty much self-explanatory. I used Leigh M&T jig for cutting tenons but other methods can be used just as effectively.