HereSphere doesn't show funscript files in the file explorer (where you browse for videos). It'll just automatically look for a matching funscript in the same folder with the same name when you play a video.
If your want to play a manual pattern, you need to start the name with "Pattern", and then place that script in the fallback script directory (default directory is "Interactive" on your Quest storage, create a folder if it doesn't exist). The script name will appear in the synchronized peripherals menu, in the manual script pattern row. You can select different patterns by clicking on the dropdown box.