•How to get free subscribers? Or did you guys just go blogging to increase your subscribers?
To get subscribers to your YouTube channel, simply just post good content that people would like to watch. There's no point getting those sort of "earn 1000 free youtube followers!" if they aren't going to watch your videos anyway.
•In making a video presentation about the campaign do I really need followers/subscribers?
It depends on the campaign. But they most likely require a certain amount of subscribers to accept you to the campaign.