Once you have your Residency as Professional Foreigner you can apply to the Work Permit. The main requirement is to have the resolution that approves your Visa and attach the copy of the diploma and four pictures. This permit will first have a validity of one year renewable. Afterwards, you will apply to the Permanent Residency in which you will need to have at least 9 months of payment to the Social Security. At this moment your work permit will also be permanent.