When setting tally enable for each available ATEM Aux buss it allows selected camera sources to flash a tally on the IO connector.
This is useful for when camera operators need to know when they are selected for an iso record etc. This tally differs from an on air tally as it flashes at a regular pace which is easily recognised. This feature can be toggled on and off as required.
Also shown here with the Aux control is the ability to save and load all Aus buss assignments. When used in conjunction with the Hot/take selectors, all Aux busses can be changed simultaneously using a single push button. This is useful for changing ALL screens at the same to for a presentation effect.
Also covered in this video is the set up operation of the ATEM multiviews. What is not shown is the icon in the bottom right corner. This allows the use of 4 separate multiviewer layouts for all available multiviewers (as provided by the ATEM).