Krypton will not load

Hi all
I have mentioned this on another thread .
I cannot get the download to it install krypton 17. I have stopped and uninstalled kodi app.manually. I have downloaded kodi17 but no automatic installation starts. I go to appinstaller .click the download selection then click install.it starts then stops saying x app not installed.
I have tried playstore ,kodi TV site and top tutorials. I used this on my other box successfully. Both boxes are identical make and model..
I have spent hours on this .
Any ideas please.
On my other box krypton looks great and easier to navigate once you sit there for a while playing about.

BTW is there a list of suggestions what legal add ons there are and how to find them. Being newly retired I want to hobbyfy the kodi idea for entertainment only not to be a technobuff. I don’t want the banned stuff but Google Glass only seems to come up with fusion and the ilk.how do I learn the uses of the rest of the menu list.
Is there an idiots guide somewhere. Some of the jargon speak can be mystifying. I am self taught pc wise.Huh
Thanks
Geoff