You can reach more drawing tools by using "combo" buttons. These buttons have a black trianglein their lower right corner.
When you click on that triangle, you can select a function from a list of options. The main combo button preserves the latest selection.
For complicated molecule-drawing you can use the Drawing tool See details here.), which enables you to create bonds without changing tools, or even releasing the mouse button. (
You can find more functionalities in context menus. You can reach context menus by right clicking on certain parts of your structures (for example atom, bond, R-group definition etc.).
You can find more details about context menus in the documentation.
View Settings give you the freedom to see the molecule as you want to. You can set valence check on/off, display options such as ball and stick, and much more useful view options.
For more information visit the View settings dialog page in User's Guide.
You can get more information about the other features of Marvin JS from the Video tutorials.