To make a macrame board you will need a corkboard (approx 30×40 cm or 12×16 inches) and styrophorm boards. For styrophorm you can easily use packaging styrophorm.
Cut styrophorm in the size of your corkboard. The styrophorm should be thick enough not to let your pins come through. If you have thinner styrophorm, make some layers of it using double-sided scotch (do not use glue as it dissolves styrophorm) to achieve the desired thickness.
Put your corkboard on top of the layered styrophorm and fix everything along the edges with a wide scotch. To make the look pleasanter you can decorate the sides and the bottom with an adhesive decor paper.