Welcome! A quick Google tells me the $75 tier is Alpha access level. Unfortunately, Alpha has not yet been released (it has been delayed for various reasons and INovae want to release a product with all the gameplay bones in place for it - see weekly updates for more)!
There are however Alpha access weekends happening sometimes so keep an eye out for those! The next one should be shortly after the next dev patch release (which is due Soon).
The only thing you need to do is make sure you are registered on this forum with the same email address you used to pledge on Kickstarter!