Update installation_instruction.rst

Hi Prof. Liberzon, I just edited the installation_instruction.rst as you requested. I tried to be as clear and detailed as possible on the way I proceded, feel of course free to change anything. By the way, I included a PS. Note at the bottom of my edits, not knowing I could send these comments, which may be the actual key to the whole thing. 

Best Regards and I hope it helps.

R.Anleu