A/C low pressure port location needed

You are going to have two of them but the high side which I assume you found is going to be located on an HVAC line. This is the discharge line.

The low is going to be on top of the accumulator. I am going to attach the info below that will show the details on this.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Please run through this info and let us know if you have other questions.

Thanks