Create New Project... -  Select this option to create a new project. The folder for the project should exist before you create the project. Ideally, you should have the drawing files for the project on your system when you create the project. That's not required but there isn't much you can do with a project that has no drawings.
When you press this button, a standard Windows Folder Selection dialog will appear. Select the project folder and press OK. The Project Properties Window will then appear, allowing you to define the properties for the project.

Open -  Open a drawing file. This is typically used to open a file that isn't part of a project, but it can be used to open a project drawing. If you are working within a project, it's much easier to open drawings using the Project Toolbar

Save -  Save the information for the current drawing as part of a project. This is only needed when you are working on a drawing outside of a project. When you work on a project drawing, your work is saved automatically.
When you select the menu option, the Drawing Properties Window is displayed. Complete the information in this window (including assigning it to a project) and press OK. All subsequent changes to the drawing will be saved automatically.

Save as TIFF file -  Save the current page of the current drawing file as a TIFF formatted file. When you select the menu option, a standard Windows File Dialog will be displayed allowing you to specify the name and folder for the new TIFF file. The existing drawing file will not be changed or deleted. The new TIFF file will not be part of the current project.
This option is not available if the current file is a protected PDF file.