How can register service in the startup.cs ? Optimizely CMS 12 & .Netcore 6.0

Hi Team,

I have implemented one of the settings service as below

public class SettingsService : ISettingsService

{

}

and register the above service in startup.cs like below
 public void ConfigureServices(IServiceCollection services)
 {

            services.AddSingleton<ISettingsService,SettingsService>();

            services.AddTransient<ISettingsService,SettingsService>();
}

but it's not calling "SettingsService". could you please help us how can we call the "SettingsService" in Optimizely CMS 12 & .netcore 6.0