Hi Txsag96,
Welcome to the Heartland Owners Forum and to the family. We have a great bunch of folks here with lots of information and all willing to share their knowledge when needed.
Not sure which unit you have, but the valve will be right at the tank outlet most likely, so you will need to drop the chloroplast down on one side so you can see the drain lines.
Be sure and check out our Heartland Owners Club. Join us at a rally when you can and meet lots of the great folks here and make friends for a lifetime.
Enjoy the forum.
Jim M