See volume by channel
The By channel panel ranks every connected channel, plus the website widget, by conversation count for the selected range. Use it alongside the channel filter at the top of Reports to open the full picture for one channel specifically.
See volume by agent
The By agent panel shows how many conversations each teammate has handled in the range, which is a useful starting point for balancing the queue — though it says nothing about quality on its own, so read it alongside response times.