Confused about AER

I’m investing in tech giants. What confuses me is the graph. At the bottom it says investment amount £1000 and then the graph shows the percentage of AER. Per month 3 months and so on.

But the calculations don’t add up to what I’ve invested 3 months ago
Please explain

Sounds like you’re just talking about the general fund performance graph.

That shows you what the value of £1000 invested x time ago would be today as well as tracking the performance of the fund over the selected period.