You work locally with a single PC or a laptop. The executable program files of the application and the generated data are all to be saved on this PC or laptop.
There is no connection to a PC-network (or you do not use it).
... the default paths are used, or
... you define the local paths for program files and data directories.
Have you read the General installation instructions?
You want to install an update?
Update within the version, e.g. from 26.0.0 to 26.0.1
Change of the version, e.g. from 25.x.x to 26.x.x