The barons provided king John with money and men for the territory
European rulers wanted to keep their powers, and so they banded together to crush revolutions that started all around Europe
hope this helps
The way people choose to go about it
I'm no expert but considering the only other country capable of reaching it at the time was Portugal, who was focused on Africa, by the time Portugal arrived in Brazil Spain already dominated the carribean basin, England and France wouldnt arrive for a long time so it was pretty much just Spain, Spain and Portugal had also agreed how to split the findings in the new world