I would like to have multiple lines, similar to that seen above however it will only let me put one value under y axis as opposed to allowing me to stack as high as possible in the series area.
If I correctly understood your question, I think it can be solved be changing the number of series in the left scale.
This propertie basically controls the number of lines (from different Series) in your chart.
Then the first "N" series on your chart will be your lines.
Trying to illustrate this:
Don't hesitate to ask if you need more help.