When the instructions came out I didn’t get Them do you still have those Instructions On building barn doors Cheaply please?
Here are barn door ideas from Hometalk: https://www.hometalk.com/search/posts?filter=diy%20barn%20doors
Here's one: https://www.hometalk.com/43331789/diy-sliding-barn-door
I just saw some sliding barn doors, with hardware at Costco. Check out in store or Costco.com. Many box stores carry the barn door hardware. Your style will determine what you need.
Ken has a good point to first check the price of ready-made barn doors. By the time you add up the cost of the lumber and hardware, if you do not already have all the requisite tools, it may not be cost effective to diy.