I haven't done this with construct, however on other platforms it can be done by storing a file.
When you're app runs the first time, you can check for a file (eg: firstrun.txt). If it doesn't find it, then it's the first time that it was run since installed. As soon as it has been run, you write the file out with 1 byte (Eg: 'Y').
The next time the app runs, when you check for the file, and it will exist, so you skip the tutorial bit.
This way, in options, if you want you can give the option 're-enable tutorial' and just delete the file so the tutorial runs next time.