In the pop-up window shown below, specify the source path as the downloaded V90GSD file, and then install it. (Another method, copy a project file with V90 hardware, open it, Portal will install V90 GSD from the project file)
In the pop-up window below, specify the source path as a downloaded V90GSD file and install it. (Another method, copy a project file with V90 hardware, open, The Expo itself will be V90 GSD installed by the project file)