windows 7 – How do I plot a point on a line of best fit?

I have a line of best fit graph on excel, and I want to plot points on it with 3 new data entries that only have Y axis values – and I’ll get X axis values from the line of best fit. How can I do this?

Here’s my graph now. I want to move the orange points over to the line of best fit.
[1]: https://i.stack.imgur.com/XLDWL.png