It says I have the integration installed, but there are no devices or entities. Does anyone have any experience with disintegration?
The integration works with a device that measures the amount of LP gas in a tank.
Yes I use the integration and it found my sensors and they work as expected.
I’m pretty sure you need a BLE proxy or some other BT receiver accessible to HA for them to work with HA.
@Scrutch - Oh yeah, lots of experience with disintegration. 
But I’m assuming you probably meant experience with this integration (Mopeka). Yes, I’ve been running it for several years, and a friend has had it even longer. We’re both running Mopeka Pro Plus units on our outdoor residential propane tanks, and I’ve got a Mopeka Pro Check on my gas grill propane tank.
As mentioned in @finity reply, you need to have some way for the Bluetooth radio in the sensor to connect to HA. By far the easiest, is just to have one or more ESPHome Bluetooth Proxy units in the general neighborhood of the Mopeka unit. The Pro Plus is rated for 1000+ foot range on its Bluetooth radio signal, but less than that on the Pro Check unit. Once you’ve got the Mopeka’s Bluetooth signal reporting in, HA just magically picks it up.
One additional consideration is that the built-in HA integration for Mopeka only provides propane fullness indication in distance (inches or millimeters). But of course it’s much more useful as tank percentage full. I’ve added on two additional HACS integrations to get that info for my two different sensors. Two integrations, because they happen to handle different tank sizes and geometries (horizontal and vertical). And interestingly, one of them also offers temperature-compensated propane volume, because the volume of the compressed gas is noticeably affected by temperature. Those HACS integrations are Mopeka Advanced (for the 20lb grill tank), and Tank Volume Calculator (for the 500 gal residential tank, which also does temp. compensation).