Rough Cut the Lumber
It's easiest to get started with this project if the flooring pieces are first cut into roughly 2-foot-long sections, so long as the rough cut width is wider than your desired width for the finished cutting board. Rip the flooring pieces. Each piece of flooring must be ripped twice.
If it's tongue-and-groove flooring, remove the "tongue" and "groove" from each piece with a rip cut on the table saw. Begin by running the flat groove side along the fence, cutting to remove the tongue.
It's fastest and easiest to rip the tongue side from all of the wood material before resetting the fence and moving on to the groove sides. After all tongues have been removed, you can reset the fence to rip off the old grooves from the opposite side of the stock.