Explanation:

Box1
Run the New-AdfsWebTheme cmdlet.
Box2
Customiize the theme files.
Box3
Run the Export-AdfsWebTheme cmdlet.
Box4
Run the Set-AdfsWebTheme cmdlet.
Box5
Run the Set-AdfsRelyingPartyWebTheme cmdlet.
The New-AdfsWebTheme cmdlet creates a custom web theme.
You can modify the .css file and configure the new web theme by using the new .css file.
The Export-AdfsWebTheme cmdlet exports the web theme to the required directory.
The Set-AdfsWebTheme cmdlet applies the .css file to the new theme.
The Set-AdfsRelyingPartyWebTheme cmdlet applies a web theme to a relying party.
References:
https://docs.microsoft.com/en-us/windows-server/identity/ad-fs/operations/custom-web- themes-in-ad-fs
https://docs.microsoft.com/en-us/powershell/module/adfs/set-
adfsrelyingpartywebtheme?view=win10-ps