The programs developed and edited in B4 are called projects.

An instance of the B4 environment can open just one project at the moment. You can, however, run more than one instance of the B4 if you have a computer efficient enough and you think it's a good idea. Each instance can open a different project.

But be careful not to open the same project with two instances of B4. That it to say, the instances cannot share the information about their projects.

You can open a new project using the File -> New Project command or you can use the shortcut CTRL+N. If you have an unfinished project (the project, which has changed since it was saved the last time), the program offers you to save the project. By virtue of just one project can be opened at the moment, the last one is discarded.

You can open an existing, saved project using the File -> Open Project... command or the shortcut Ctrl+O. B4 will open a dialog at first. When you use the dialog to specify a file containing the project, the project is opened.

You can save the current project using the File -> Save Project command or the shortcut Ctrl+S. B4 saves the current project to the file.