Remember checkboxes in a file, PHP to-do list

I'm creating a personalised pin board, kind of to-do list. I know how to (1) add text to .txt file and (2) display it above the textbox and buttons, but I also want it to (3) create a self-unique checkbox, which I'd be able to (4) check/uncheck and (5) remember their states (to every next session). I'd be so happy if I also could (6) delete them from the list somehow.

I can storage that in files, there's not going to be much of created tasks and I don't need superextraquick requests. I need it relatively easy to learn because I'm such a newbie; and possibly not using js.