Still didn’t answer, but I eventually found that you cannot pause live tv on this model. Seems very poor that it’s not available on this and quite a number of other Samsung TV’s. Now got to look at other brands.
It should work as on any other samsung TV (2k18+), its a timeshift feature. You just need HDD connected and then you can pause live TV ("pause" it will start recording the content so you can watch it ), anyway It would be much simpler to use some IPTV with backwatch feature than old fashioned timeshift