Help on setting path right
This is how it worked for me: 
1. Render invisible files visible.
2. Then open the bash_profile in your home directory with any text editor and write down whatever you need to, f.ex.: 
'export PATH = /this/is/some/complete/path/name:$PATH'
Adding ':$PATH' lets the system search for other pathnames stored somewhere else (so do that only when editing system variables). 
':' in general enables you to ad multiple paths.
3. Don't forget to reload the affected files by typing into the bash 'source /filename', for the changes to take effect. 

Other problems you might encounter:
When defining multiple variables be aware that it parses in order, so if you use f.ex.
'export PATH = $ANOTHERPATH/some/directory' 
make sure to define ANOTHERPATH before defining PATH. 

And make sure you really know your OS's file system.