A single click will open any item on the Dock.
When a program is launched it bounces on the Dock.
If a program is running it has a white glowing dot underneath.
You can remove an item from the Dock by dragging it off.
Any programs not on the dock can be found in the Application folder.
If a program is running it will appear in the Dock.
Right/Control clicking on the program icon pops up a menu that allows you keep an item in the Dock.
If a program is minimized it can be returned to full size by clicking its’ icon.
Any minimized open windows can be found under their icon in the Dock and re-opened by right/Control clicking and choosing the document name from the pop-up menu.
You can add folders to the Dock by dragging them to the right or lower end of the Dock.
You can re-position icons on the dock by click & hold then slide them along the dock until a space opens up where you want it to go.
Folders open up in two configurations click once on Dock icon then once more to select file or program.
Right/Control click on the Trash to empty it.

Menus are very useful, there are two main types of menus. Ones that are specific to the currently running program, these are found at the top of the Finder window. Context Menus are found wherever you Right or Control click with the mouse, these perform actions on the clicked on item.
One thing of importance to note is that the menus are always different from program to program and item to item.