Mr. Romanov the 1734 - AENTR has the connection for power and ground. what is the second channel for?
It’s a bit confusing due to the modularity of these cards. For the IB4, you’ll be using the top 4 connectors for the Inputs, and the bottom is power (you shouldn’t need to connect anything in the bottom 4)
Here’s a reference:
You don’t need to cover an open base, but I probably wouldn’t leave them in place. Just remove any bases that aren’t utilized in the system.