The easiest way is to simply drag and drop the zip file into the CM window. Those three stripes next the 'about' tab at the top right will turn green. Click that and press install (this also works to install most car/track mods).
You then enable the patch by clicking on the 'Content' then 'Mods' tab.
I normally install all mods via CM drag 'n' drop but I'd read in a few places that Sol shouldn't be installed that way (which did make me wonder why Peter hadn't set it up that way). Good to hear it does work, as I've got to reinstall Sol to get my clouds and moving sun back.