Business visa--VIVIS

Hi,   I will high appreciate that  someone can help me answer below my questions:

The main information of my visa is :

1. My Visa type is VIVIS;
2. the Issue date is 28th Sep;
3. The Expiry date is 27th Nov;
4. the Duration of stay is 60 days;

my questions is:
1. do I have to first enter Brazil before 27th Nov?
2. if I enter Brazil on 27th Oct,  when I have to leave  Brazil?  before 27th Nov?
3. For example,  if I enter Brazil before 27th Oct, and then apply for the extension for another 30 days,   if the application is approved, can I understand that,  before 27th Jan 2019, I can enter Brazil multiply since the new duration is (60days+30days=90days), but the total multiple duration of staying in Brazil shall be within 90 days.  Am I right?

Visit visas can be granted for those traveling for tourism, business, transit, artistic or sports activities, study, volunteer work, or to attend to conferences, seminars or meetings, among other purposes - provided there is no remuneration in Brazil and the stay does not exceed 90 days.
The key is you have 90 prior to expiring date. You would have to have it extended and go to the PF.