Puppet - how to apply module to puppet client node?

You haven't declared the module (assigned it to your node) yet...

Add this to site.pp:

node 'fqdn of client' {
  include yum
} 

Then, you can run puppet agent -t to see it in action.

Try to use Hiera and yaml files, I think it is much more flexible and better organised.

Edit the site.pp file:

node "default" {
    hiera_include('classes')
}

After that you can call the classes in every of the specific node.yaml file with simple:

classes:
  -class1
  -class2

I am using it on Ubuntu, works fine.

you can use the following command to view the details output

puppet agent --test --trace