You will be able to set a unique name for your Ruuvi sensor in Ruuvi Station mobile app on sensor settings page as well as on dashboard by choosing Rename from the three dots menu.
On web, open full sensor card to view sensor settings or choose Rename from the three dots menu.
Ruuvi Station will use unique (Ruuvi + last 4 characters of sensor MAC address) as new sensor name by default, but you are able to name them freely just by tapping on the Name field and adding a preferred name.