First of all - im really brand new on HA - as in… 3 weeks of experience 
I’ve bought this one on AliExpress:
When addin it to HA i am not able to see anything, but 2 disabled entities.
(sorry its in danish)
“LQI” and “RSSI” is the disabled ones.
I can’t get eny temerature readings or anything from the device.
Where to start digging?
Thanks in advance.
Looks like you started off at the deep end! Start here
You’re probably not wrong 
- digging in the deep end is my speciality.
I’ll look into your link, and return. Thanks
I wouldn’t set my expectations too high. Even in Z2M (which usually has much better device support), I could only find one reference with partial support for your specific model.
Hopefully that should be enough to help you get started. If not, there are plenty of other supported temp & humidity sensors available - have a search here and look for the ones with the homeassistant logo.
Yeah ok - caught between a rock and a hard place.
It was the only zigbee device I was able to find that had a metal probe - and it was actually a second choice. I was going for a pipe-temperature-measurement device, to measure the “return” temperatur of my hot water supply.
If it doesn’t work - it doesn’t work. Then i’ll try something else 
Oh, so you actually need a temperature sensor with an external (waterproof) probe? I might have seen a couple of supported ones. Do you need it to have a screen?
It doesnt have to be waterproof, I’ve seen some with a clamp on, that is just mounted on the iron-pipe. It does not have to be 100% accurate. But of there is any valve-like that pass water through, that would probably be better.
Thing is, that i have changed all my thermostats on my heatingsystem (waterbased), and since they only open up 100% untill temperature is reached (TADO), the return-heat is to high.
I’ve made my own measurements on the return-heat, and i just need to make that temperature define, when the Tado’s need to turn off, instead of the room temperature. Makes sence?
Almost 
Most thermostats come with an option to add an external probe.
There are specific fittings you can add to your pipe to install a probe, so that part should be covered too, but you might need to speak to a plumber.
Eg:
Version with screen (has an NTC connection at the back, so you can use a regular NTC probe).
Version with battery & without screen
If your not afraid of DIY, Ds18b20 with an esp32c6 is what I went with, cheap, easy and no quirks required.
