17 with two projections set parallel to each other. Make all the frames of the tabernacle in this way.

Read Exodus 26:17 Using Other Translations

Two tenons shall there be in one board, set in order one against another: thus shalt thou make for all the boards of the tabernacle.
There shall be two tenons in each frame, for fitting together. So shall you do for all the frames of the tabernacle.
with two pegs under each frame. Make all the frames identical.