Scroll screen in EV3 Home Edition program
Using the mouse, you can click on the gray arrows on the edges of the screen (indicated with red arrows below). You will need to close the Content Editor to be able to see the one on the right clearly.

Another option using the mouse is to use the "pan" tool. Click on the tool icon that looks like a hand (circled in red below). Then use it to click and drag anywhere in the work area.

You can also use the keyboard arrow keys. First click on any blank white space to make sure that no blocks are selected, then press the arrow keys to scroll.