Note this isn't a board it's a panel, multiple boards joined together.

Go to home depot's website and search for 'barn wood'. That will give you choices for fake reclaimed wood boards like this. You can't just stain wood to look anything like this, it has to be distressed and you probably don't want to do this yourself. You can buy the boards and glue/screw/nail them to a plywood panel, which you can also buy from home depot in 24X48 size and cut down.

After you paint it you can leave as is or chose to cover with a clear coat like water-based poly.