Hi Rogerio
Assuming this is MRS 9.0 fist go to the following web page:
Now you will find lots of useful information there but then on the section "Configuration and Deployment Information" click on SAP Marketplace. (You need OSS user id and Password)
And then download the solution manager document.
In that document you will find the configuration guide.
As some parts of configuration may need the touch of HR (especially for the evaluation paths), you may need some help from HR department.
Make sure that you have applied all of the required OSS notes. (i.e. For activating MRS for PS, you need to apply several OSS notes. Make sure that you have done them all.)
There are at least two batch programs you need to run. Don't forget running them in order to move HR data from HR to MRS in order to be able see your resources.
I hope this will help.
Cheers
Savas