Hi Novatian,
As far as I am aware selinux is enabled and runs in targeted mode by default in Fedora 16. So, you do not need to do the tweaking. However, you can run the following command to make sure:
Above command will let you know if selinux is enabled or disabled and if enabled then which mode it is running whether permissive or targeted.
If it says disabled then you have to edit /etc/selinux/config file as mentioned in that document and enable it. Reboot the system so that it can relabel the filesystem. Once done you can check the mappings by the command mentioned in the document that is: /usr/sbin/semanage login -l
I would like to mention that you enable selinux only when you are aware about how it works. selinux when running in targeted mode may cause issues with some applications. And if you are not good at selinux you might find it difficult to troubleshoot the issues.
Small tip if you plan to go with selinux: make sure you setup selinux booleans and contexts correctly when configuring any application.