Create UserCustomAction for SharePoint Framework Extensions (Tenant-Scoped)

I have created a SPFx Extension (Application Customizer - Tenant Scoped) and I have uploaded it to the App Catalog succesfully.

Now I'm trying to add it in a Site creating a UserCustomAction, but I'm getting the next error:

'ClientSideComponentId and ClientSideComponentProperties are not supported for actions that are not used for client-side extensions.'

This is the code for the creation of the UserCustomAction:

... // var colCustomActions = cc.Web.UserCustomActions; // << also tried in the web var colCustomActions = cc.Site.UserCustomActions; var newCustomAction = colCustomActions.Add(); newCustomAction.ClientSideComponentId = new Guid(guidFromTheManifest); newCustomAction.ClientSideComponentProperties = ""; newCustomAction.Update(); cc.ExecuteQueryRetry(); 

Any hints? Do you have an example of the code for the creation of the UserCustomAction?

Thank you very much in advance.

Best regards.