Moving from tricaster to ATEM?????

I am currently using a tricaster to run live internet. I would like to switch to ATEM but have found Black Magic people very un-helpful.

We run an internet tv station and want to duplicate what the tricaster does on ATEM. We also want to move to Mac which is most of our gear anyways. Here is what I am not sure of:

1. How do we run live on the internet with ATEM. We are using IMAC. What gear do we need other than the obvious stuff. BM won't recommend the products that actually make it all work.
2. What do we use for CG's storage, playback (DDR)

THis would be just part of the questions but I am not sure what to ask. Can anyone help?

Thanks
George