Few hours ago Valve made a blog post that confirmed the rumors that were circulating on web about the new system. For instance, it is now certain that the first Major will take place in Europe at some point in November but there is no disclosure of the country where it will be held nor specific dates or if it will employ third party organizers.
The announcement states that the tournament features both Open Qualifier and Regional Qualifier. One day before the Open Qualifier will start, on October 5th, several teams will receive a direct invite.
The Open Qualifiers will take place from October 6th until October 9th and will be followed by the Regional Qualifier from October 10th until the 13th.
“Any team may participate in an Open Qualifier, and two teams from each region will be among those invited to participate in the Regional Qualifiers. The Regional Qualifiers will then determine several of the teams to be invited to battle at the Major.” - Valve
For teams to be eligible for either the direct invites for the Regional Qualifier or the Major directly, they must finish their roster changes until September 5th 2015 at 12:00AM PDT. Any team that will undergo changes after that will lose their chance for a direct invite.