How to Check the Coolant Level in an Audi A3?

I recently purchased a used Audi A3 and I want to make sure the coolant level is at the correct level. What is the best way to check the coolant level and what should I do if it is too low?

First, locate the coolant reservoir in the engine bay. It should have a blue cap with a coolant symbol on it. Use a flashlight if needed. Then, check the level of the coolant against the the line marked as 'MAX' or 'FULL' on the side of the reservoir. If the level is below the line, you will need to add more coolant. Fill it up to the 'MAX' or 'FULL' line using a mixture of 50% coolant and 50% water.