In my experience those little rebuildable heads are really frustrating and don't work very well once done properly.
A drop in
tank can be just that and an RTA can offer a prebuilt solution but I've never seen a subohm
tank with a drop in rebuild deck that worked well.
When I started it was using the RBA head on my crown
tank and I hated it. Always either too tight or leaking and when I made it work it was a horrible vape. Then I got an RTA and nailed it first time.
Usually when you can't find info on something it's because there was no demand for the product or the tutorial.
If it came with something pre-installed I'd try to replicate that.
It should at minimum have instructions with a picture of what it should look like.