Bill, The door glass runs must be installed/fit first. Then the runs must be lifted up to unhook the top clip of the run. The door glass/channel assembly is then slid down the runs. Once the glass is installed, the runs must be re-installed at the top.
If the glass runs are glued into the run retainers, then the above will not work (can't move the runs up/down). I don't know how to get the job done if using glue (not original).
I can send you photos that might help with your project. Email neil@aafords.com