The case bottom will be attached to the side assemblies using stopped, sliding dovetails. One of the horizontal dividers will be a full shelf and similarly attached. The bottom shelf will be fronted by an apron attached to the legs with mortise and tenon and glued to the shelf. Which means that no mahogany is necessary on that work piece. The horizontal divider has a three inch strip of mahogany for the show edge but no back mahogany edge as that will be behind the case back (design of which is still being pondered).
The router jig shown is from Marc Adam’s timely FWW #282 article. A dado is routed with a 3/8 inch straight bit just shy of full depth (1/2 inch) in two passes. After the four dadoes are cut, the jig is reversed, aligned and the sliding dovetails cut in one pass with a 14 degree dovetail router bit to 1/2 inch deep.
Next the two panels of poplar are glued up and milled to approximately 3/4 thick with edges of mahogany where appropriate. These panels will have sliding dovetails cut to fit the case side dovetail slots.