Trim. Trim. Trim.
Getting the hatch to fit meant trimming and sanding the walls down. I wanted the hatch to be a little higher to account for foam or trim so adjustments had to be made.
Once satisfied about the fit, I glued and nailed the crossbeams in. That was easy.
The hinge was hung up, I thought, in delivery. Then an email arrived that UPS had somehow damaged it. The hinge company had already re-sent me the product and it was due tomorrow. Cool!