Welcome to the forum!!
Sailboards are a lot of fun...........I started sailing on them in the early 80's.............Unfortunately I could not find a centerboard for your board. Might check with a local windsurfing shop to see if they have one that would fit. Also I could not find a manual for your board and I do not even recall having a manual for my windsurfers so suggest doing an internet search for youtube videos on rigging and sailing a windsurfer. Hope that helps.