Political and conceptual
Q: OpenSCADA is unclear and hard to understand one. Why is this, and are available the manuals quickstart and advanced "How to ..."?
Re: OpenSCADA has described in detail, maximum structured and formalized. But the unclarity and the complexity impression is expected. Based on the project objectives, the program is extremely modular, which means that there are a lot of configuration and usage options. On the one hand, it complicates perception, but on the other - it increases the chances of "coverage" of your particular task. In addition, you must always remember that the complex and incomprehensible are all the unknown, which is really not necessarily so. And this psychological barrier must be overcome when studying anything new. The quick start manual is available here and the advanced "How to ..." also here.