Ask a mod to move this to Trikesylvania so you can get some tech help.
This forum is for custom fabrication/engineering etc etc.
They are also very harsh against pics without a helmet. Don't shoot the messenger, I'm just giving you a heads up....
I'm gonna guess you don't have a manual or you wouldn't ask about the side bolt which is just the drain bolt.
Such a nice trike,cheap, why not download a manual before you ruin
parts??
With the springs out, lower bolt out and the clip off, you have to put the lower leg in a strong vice and use a

ing action to remove the upper portion, seal 1, seal 2, spacer and the damping rod assembly with lock ring.
I've done dozens of forks and never used any heat on them....
Please, look around and download the free manual, at least then you won't be wasting your time.
Anyhow, Great find and welcome to 3WW!!