Folding editors can help. Maybe also if there were a thumbnail of the file in a sidebar, with a rectangle representing the current viewport, that could help reduce the anxiety, by giving you an estimate of how much more is there off-screen.
Beyond that, it's part of the course. Nowadays you will not get to work on a production anything that all fits on your screen. Individual files might, but they are part of a whole that doesn't.
Self-contained programs that fit on the screen are able to do that because they reference a language, and that language is not on your screen. You learned the language and so you don't have to take your eyes off the program to look up the documentation or source code.
Beyond that, it's part of the course. Nowadays you will not get to work on a production anything that all fits on your screen. Individual files might, but they are part of a whole that doesn't.
Self-contained programs that fit on the screen are able to do that because they reference a language, and that language is not on your screen. You learned the language and so you don't have to take your eyes off the program to look up the documentation or source code.