Cisco ACI - any recommendations for training myself?

So my company is putting in some ACI infrastructure and I wanted to get some self teaching going to learn more about how to configure them as it's a bit of a shift away from traditional Cisco config with the gui, tenants, policies, etc

Can anyone recommend some online (free) training or lab setup guides etc to get my feet wet here?

As per usual, there will be very little training from my company itself. So I need to do a fair bit of my own back here.

Thanks