First, log in to your 3CX web client, then click the 3 dots below "Contacts" and select "Recordings"
Then, find the date AFTER the day of the call you want to listen to. Each report is generated at 5am for all calls within the previous 24 hours, so the date is off by 1 day.
Click the "Search" button and it will open up a new window.
Then, find the call(s) in question. Click the checkbox next to the call(s) and select the "Download" button at the top of the screen.