As far as I could understando you want to create the level (save the input and time of input) AND read it for your game, right?
I'd suggest using EOF, a program specifically designed for creating levels for rhythm games. It may seem complicated at first but there are lots of tutorials and you'll surely grasp it quickly. It generates a XML file with looooots of information about the level, including diferent note sets for different difficulties. Anyway... Use it instead of trying to reinvent it on Construct.
For reading it you could use the XML object or, if you prefer, get the information on the generated XML and adapt it to the loading format you want to use (Array, JSON, whatever).
Hope this helps...