Take a look at the Samples below to show how this works.
Android makes DI more difficult - you need to set CrossJob.ResolveJob = (jobInfo) => return IJob in the MainApplication
for iOS, you can set it the AppDelegate or Xamarin Forms initialization like you normally do
Autofac is also a little more difficult because it is an immutable container. Take a look at AutofacRegistrationSource in the sample to see how to forward types