As an ex 6502 programmer from the 80s, I struggle with modern software, terminology, syntax and programming methodology. I have little experience of Linux, Java and until recently had never heard of AngularJS and 'reverse proxy' and thought Json was a character in a film. Thanks however to Openhab, the developers, the community here, Google and the documentation, I have a rather nice home automation system on my Raspberry Pi.
A few suggestions from my experience:
1) Get it up and running on Windows first. Apart from setting the JAVA variable (solution found by googling) after installing Java, it is easy. Unzip the distro, store in a directory off C: and you are up and running in minutes.
2) Spend time exploring the demo. See how the items, sitemap and rules work together.
3) Check the file structure. The locations will be different on say a Raspberry Pi but you can explore, check the logs etc.
4) I renamed the demo files as 'home' changed the site name and modified the demo for my own system. It saved starting from scratch.
5) Get simple items working first before moving to complex bindings.
6) I use a Raspberrry Pi and found there were no problem following the documentation for installing Raspbian and then Openhab. Make a note of each step so you can easily repeat the process on a blank micro sd card or preferably buy a spare. (I haven't tried Openhabian yet)
7) I wanted a password log in for external access and found I needed to use 'reverse proxy'. There is an excellent thread here that tells you how to set it up. I haven't a clue what 'reverse proxy' is, hadn't a clue what I was doing when I followed the instructions but it worked.
8) I didn't like Eclipse Designer so I use WinSCP for setting up the configuration files on my Raspberry Pi. This allows me to modify the files on my Windows PC and upload to the raspberry Pi. No messing with the Raspberrry Pi OS and their desktop.
9) Try Habpanel, it's awesome.
Finally, enjoy your FREE software.