Kant Vocab

Your will is your practical reason. In other words, your will is what allows you to identify what is good in terms of certain goals (23).

An imperative is the form that commands take. The representation of an objective principle insofar as it demands the will be a certain way is called a command of reason. The form of a command is the imperative (24).

Hypothetical imperatives are commands that must be followed in order to reach some goal (25). Hypothetical imperatives are commands to perform actions as a means to an end.

A categorical imperative is a command that must always be followed because the action is good in itself. In other words, a categorical imperative is a command to perform an action that is good as an end (ibid).

A perfect duty is a universally necessary duty (30).

Imperfect duties are duties that we must sometimes perform (ibid).

Properly speaking, Kant says that true 'duty' is always categorical (33).

There are three practical principles of the will. First, the ground of all duties lies objectively in the form of universality. Second, the end of all rational beings is rational beings. In other words, rational beings are ends in themselves. Third, the will of every rational being is a will that legislates universal law (autonomy of the will).

An end is a purpose or goal.  A means is the way of achieving that goal/end/purpose.