What do you mean by “I can’t add their entities”. If you know the MAC (or UUID), you can add it to devices (add device…), if it isn’t auto-discovered (or if you have discovery turned off).
If it is a supported sensor, it should add it as soon as it gets the first BLE message. If it isn’t a known format, you can only use it as device tracker (enable that option).
If this is not the answer you are looking for, please try to explain what you did, what you expected to happen and what happened.