Click on the icon highlighted in the picture below:
A confirmation message informs you that the company exists on the platform. If the name of the company matches your customer's company, confirm by clicking Yes. Note: the status updates to Connecting mean your customer has not yet accepted the connection. They can accept it as shown in step 5.
Your customer(s) will receive a task in their own account, informing them that you're trying to connect with them. Your customer(s) must approve the connection with you.
Once the connection is approved by your customer, the status will be updated to Activated.