Basically, the FixMKVGaps application does not require any installation.
When you download FixMKVGaps from Paul Glagla’s site, you get a compressed file like fixmkvgaps_xxfr.zip .
Just open it with any application that knows how to manage compressed .zip files and extract the executable file, like fixmkvgaps_xxfr.exe, to one of the folders on your hard drive, or even to any external storage device such as an USB key or an external hard drive. The application is then installed and ready to work by double clicking on its icon.