Hi @SamGoody21,
In general, screenshots aren't usually too helpful for debugging code. It is easier for me (or others) to help if you create a reproducible example. This means providing the code (as text, not an image) that we can copy-and-paste to our own sessions to try and reproduce the same error.
However, the code isn't enough, we would also need the data you are running the code on. If you are not able to share the data, then you should try to reproduce the error with some "fake" data.
Try running this code to make sure everything is working fine:
ggplot(iris, aes(Sepal.Length)) +
geom_histogram()