I use to create benches often back when I was building my driftwood furniture
It's a bit different now when you are using a bedframe from the 50's vrs.
raw tree parts that have floated down the river.
This footboard measured 50" wide, divide that by half you get 25"
which is way to deep for bench arms.
So when you use a foot board for your bench sides you are going to loose a
good size piece in the middle as you can see below.
I secured the sides into place with 4" screws.
Next I cut a 2" x 4" to be the front cross support.
Mark the height your cross piece needs to sit at and when you don't have
a helping hand you can use a pair of clamps to hold your board in place as you screw it in.
I added some decorative angles under the 2 x 4 for added strength.
This piece was used for a time in our Mudroom: