Most RV's have a dual bottle rack like this:
https://www.amazon.ca/Manchester-Tan...%2C169&sr=8-11 Link is for the full kit on Amazon Canada site.
If you only have a single bottle, your X19H easily has space for this, and it just takes a couple of self tapping screws to hold it in place. If you have 2 bottles already, you may already have the base plate; Jayco was at times too cheap to include the whole thing on some HTT's and just put bolts through the tank bottom rim. When I added this on my pup, it slid perfectly between the rails for the tanks. My HTT already had one.
There are other options as well on Amazon; just search RV Propane Tank Holder.