There are a number of ways to get help:
To start interactive help, run the following command:
help()
To get help with a function or object, run the following command:
help(object) help(function) <object>? <function>?
For tab completion, start typing the name of the function/object/method and press Tab.
To get a tooltip, start typing the name of the function/object/method and press Shift + Tab.