The superfluous glue around the dowels should be carefully wiped off.
Likewise in gluing up framed pieces, sections may be put together separately: as, the ends of a table, and when they are dry then the whole may be assembled.

When the pieces are together the joints should be tested to see that they are true, and that there are no twists.
A good way to insure squareness, is to insert a diagonal brace on the inside, corner to corner, as in Fig.

294, p.195.Such a brace should be provided when the trial assembly is made.

Another good way to insure squareness is to pass a rope around two diagonally opposite posts, and then by twisting the rope, to draw these corners toward each other until the frame is square.
The superfluous glue may be wiped off at once with a warm damp cloth, but not with enough water to wet the wood.

Or by waiting a few minutes until the glue thickens, much of it can readily be peeled off with an edge tool.