Google-sheets – Google Sheets graph jump by 1 on the horizontal axis

What you need to do is a few steps:

1. Insert to Chart then add your Data Series, as you normally would with a Single Axis chart.
2. (Optional) Change chart type to Line. You can change it to anything else later. Line seems to be a safe bet for the later options to appear. Not sure if this step is by Google design...
3. Right-click on the chart and select Series.
4. Change Apply Series to whichever Data Series you want to move to the Second Axis.
5. Change Axis to Right Axis.
6. Now you can go back to Chart type to make it a scatter, or bar, or anything else - the program will remember the Axis assigned to the Data Series, regardless of whatever options may be available.

tldr; the Google Support answer is broken for a few chart types. Do your Axis assignments with Line charts, and change the Chart Type after.

Never mind, I found the solution.

It was because my data was text format (despite changing the formatting many times in the format options). To counteract this I had to make another table which used =VALUE(cell) on each piece of data. This gave me the numerical value allowing me to make graphs successfully.