One concept that should not be foreign to you by now is that of “automatic investing.” Automatic investing is the process of investing money without having to do anything additional. The beauty is that you don’t need to think about it. It just happens.
One approach to this is the “pay yourself first” model where you allocate money to go into your different accounts then you put money aside for want items. J.D Roth from Getrichslowly.org explains that:
To pay yourself first means simply this: Before you pay your bills, before you buy groceries, before you do anything else, set aside a portion of your income to save. Put the money into your 401(k), your Roth IRA, or your savings account. The first bill you pay each month should be to yourself. 
Saving now means money later.
The next step of the process is setting up an investing account that you put the money you save in each month automatically. This way you don’t even think about it and from the first time you set it up it’s already a habit.
So automatic investing simply put is investing each month without doing anything once you set it up. Beyond this the path for investing diverges into “Passive Investing” and “Active Investing.”