The pre-release in principle is a single executable file, and it assumes that a full Wren installation was performed before.
With Wren version 2022.3.25.0 or later this can be done from within Wren - but it needs Installer.exe to be present in the folder containing Wren.exe for this to work.
You may want to make a copy the existing wren.exe before you do this, to have an easy way back (for in case there are unexpected issues with the pre-release). But once the installer is there you can always go back to the full release.
You can download the installer by using this link and for Wren versions before 2022.3.25.0 it needs to be run standalone one time. With version 2022.3.25.0 it can be run from within Wren.
And the details for it can be seen here.