1. It appear's the water got beneath finish and stained wood. Repair is challenging for a beginner. Complete removal of finish,bleach water stain from wood,touch-up color to blend then apply x coats of clear finish. I can't tell how top intersect's with front,rear and sides but laminating might be possible. Actually,laminating is possible,it's only a question of how much effort and skill would be required. A cover like you have on it is what most people do.

Thank you so much for your advice. I will try stripping, bleaching and re-staining.