If you choose the Pro Plus tariff or a higher tariff, you can create multiple member areas. You can switch between the member areas in the top right corner under "Switch area".
If you create another member area in addition to your first one, you will first be shown again that you have a 14-day free trial period.
To activate this new member area permanently, switch back to your main member area where you booked the tariff. Here you can simply link more member areas under Account > Link Accounts.