Work and residence permit (Bratislava)

Hi there! I don't know if any of you can help with my issue, but here it goes:

I got offered a job in Bratislava. To work at an advertising agency. I'm Brazilian, and I currently live in Brazil. This is the agency’s first time hiring someone from overseas, and also my first time getting hired overseas, so neither of us know exactly what we're supposed to do in order to get the work/residence permit.
We try to reach the Slovakian embassy here in Brazil with no success. I already filled out the work contract. My biggest doubt is: do I travel there without the work visa (as tourist) and get all the documents done there, or do I need to apply for the work visa here in Brazil? Do any of you know?