Autofac not support to bind IServiceCollection

Question

I am doing dotnet migration from dotnet core 2.2 to 5.0. autofac implementation of dotnet core 2.2 as below, enter image description here

but i couldn't see how to populate IServiceCollection into Autofac container. it is difficult to implement with assemblies because there are multiple assemblies. How can i effectively implement Autofac container with ServiceDescriptor list. Thank you CK