Just clamp the jig to the parts youre joining, drill a couple of holes ... Cut short lengths of dowel the same diameter of the hole. Spread glue onto the dowels and cut the piece as flush as ...

A dowel jig like the Lieberwell jig kit can simplify things. Or, you can use a tape measure or try a tape hack to line up your dowel holes. Drill a hole in one of your 2x4 legs with a brad point ...