Electrical help needed!

Hoping someone can help me out...

Purchased a new dash wiring harness from year one model #HU309A for my 68 cuda. I recently installed my heater box and controls without an issue. There is no wiring from the heater box to the controls, and no female connector on the new wiring harness to connect to the controls too. I have looked online and have only seen additional harnesses for A/C /heater cars. I am lost when it comes to wiring... Any suggestions on how to complete the heater wiring and/or any kits available?

Nick