Use adhesives such as E6000 or super glue to permanently bond the pieces together. The tolerances in the parts have a 0.2mm clearance for parts that need to be connected.
Insert the legs into the body first, then apply glue to the base. Be sure to align the legs by inserting them into the slots. Inserting the legs into the body before gluing helps properly align the legs.
These have tight tolerances which gives the board a bit of flexibility but enough rigidity to move around.
Assembly is like a puzzle game that doesn’t take too long. Simply snap them together. Each square is a standard 5cm piece which makes a full size 40 x 40cm chess board. The chess board requires no glue and everything just snap fits together.