In the HPCN Portal, the Reference Check stage looks like this:

Read the instructions carefully, and when you are ready to upload references, click on the "Add a Reference" button.

You can then choose whether you are uploading a customer or supplier reference:

Fill out the required information for the reference and click "Add".

Once you have uploaded 2 customer references and 1 supplier reference, the HPSC will conduct reference checks and contact you if further follow-up is required.

Once the HPSC is finished the reference checks, they will approve this stage and you will receive email notification that the next Stage is open for you.