The affiliate dashboard shows totals, not sources. To know which content works, track on your side.
USING YOUR OWN PARAMETERS
Where the link format allows additional parameters, you can append your own identifier to distinguish placements. Check what the programme supports before relying on it.
USING YOUR ANALYTICS
Set up outbound link tracking in your analytics tool. This shows which pages produce clicks on your affiliate link, which is most of what you need.
Combined with the dashboard's conversion figures, you can work out roughly which content converts.
WHAT TO LOOK FOR
Pages producing many clicks but few conversions: the audience may be wrong, or your framing may be overselling
Pages producing few clicks despite traffic: the link may be poorly placed or the recommendation unconvincing
Pages producing steady conversions: write more like those
WHAT NOT TO OVERANALYSE
With small numbers, apparent patterns are usually noise. Judge over months, not weeks.
THE PRACTICAL ANSWER
Most affiliates find one or two pieces of content produce almost all referrals. Find those, improve them, and write more of the same.