I guess this thread is about rhythm games now lol.
DigimonFuzion10 Are you new to making games? I think there are bigger challenges ahead beyond the initial "creating arrows with tails". For example, if you have a 4 minute song, then you probably don't want to have your entire chart loaded at once, because you might have 1000+ arrow and tail objects existing at once, all moving, all being checked for keypresses. This might make your fps drop below 60fps on lower end computers.
I'd recommend using an "array" to store all your arrow data, but arrays might be a challenging thing to learn about if you're new to making games, but I highly recommend learning about them - you could read the Construct documentation about arrays here. Arrays can store data and are good for lists of objects (a rhythm game is basically a list of arrow timecodes, how long the tails are, what arrow key it is. An Array can store all of this information). You could then use the array to detect when to spawn arrows in, so that you only have about 5 arrows existing at any given time. This means you have much more room for performance, like having FNF characters in the background and more effects and stuff.
I suppose you're only having a bit of fun though, as you are making a FNF fangame - But if you find that you LOVE making games and you want to improve your rhythm game in the future, then consider learning about arrays!