Our table extension is nothing more than a piece of "flat half inch wood the same width as the table top and about 12" long" stained to match, attached to the end of the table with a piano hinge. There's a plastic strap to hold it in the folded position. Unsnap that strap, it falls down and you swing it out, level with the table top, slide a "bolt lock device" from under the table to lock it in position. When you get ready to fold it, lift it up slightly, slide that bolt lock back under the table, fold the extension under the table and secure the plastic strap.
Here's a link to the type of "bolt locking device" that's on our table:
https://www.amazon.com/Metal-Drop-Le...57300177&psc=1