Cell is a graphical file manager for OpenComputers that allows you to browse files and open them in other programs, such as the editor or simply running .lua files.
You can also customize what programs can be used to open files through the programs.cfg file.
Tutorials:
Browsing files/directories
Select files/directories by clicking on them in the panel on the right side of the screen
If a directory contains a large amount of files or sub-directories, use the arrow buttons to scroll through pages
To go up a sub-directory, click the up arrow