The first thing you’ll need to do is select a performance group. Next, set the independent and dependent variables on the X- and Y-axes respectively and explore the dependency between them. For example, you can see how the number of impressions, clicks, conversions, and their ROI change based on the overall campaign ad spend.
You can also check on individual goals by selecting them in the “Current Goal” row, which displays values corresponding to the current goal. Click on the scenario curve and set your desired goal as the X-axis to find out which parameters correspond to it. For example, you might be using a Cost/month goal but would like to find out what happens if you switched to target ROI. All you’d have to do is set ROI on the X-axis to see which goal value (shown in the “New Goal” row) would deliver your desired performance.