Once SR4 is installed there should be an icon placed on your desktop and double-clicking on it is all you'd need to do to launch it.
If for some reason there isn't a desktop icon, the file name to look for is
ScreenRecorder.exe but it may be in a different folder than PD. No matter what, it should also be available from the Plug-ins menu inside PD.
As for the multiple Profile Analyzer options, you're getting those because you have clips in different sizes, formats, bitrates and frame rates on your project timeline and SVRT can only do its magic with one of the displayed sets. It will use CPU encoding for the non-matching clips which is often slower than using hardware acceleration but it is usually of higher quality.
Your guide to choosing which of the available options should be determined by the pixel size you want your finished video to be. Since you have 4K clips you might want to use that so you have the best possible detail and quality in your 4K clips. PD will then upscale all lower resolution clips to match using the CPU.
If you're happy with HD (1920x1080) quality, choose that profile and your HD clips will be copied directly while the 854x480 clips will be upscaled and your 4K clips will be downscaled by the CPU.
Each choice affects the total production time, but that's unavoidable when working with clips with different resolutions and you goal is simply to decide on the final output you want and let PD make it happen.
If all these clips are needed to create your initial video before going in and adding any zoom keyframes as was described way back at the start of this discussion, you would want to produce it to your final desired resolution (even if you use hardware encoding and not SVRT at first) and
then let SVRT produce the edited project to the same resolution again so you won't re-encode any unchanged frames.