Visa/work Permit

Hey Guys,
I'm in the process of starting a new business, my 3 business partners are from the UK but I am from NZ, one of our businesses will be in Portugal and I will be there quite a bit for months at a time, maybe even years at a time. Can anyone shed a bit of light on the best way to go about work permits etc? Are there any other kiwis or Australians on here?

Any help is so much appreciated!

Thanks guys :)

Jess