clarification on (household) close contact testing please

[delightly]

Can anyone help me with this query please as I can't find the info online.

We have 4 people in our household, person A and person B are both positive with A starting symptoms on Monday and B on Tuesday. C & D are so far fine and showing negative on LFDs.

Do C & D test for 7 days from when A first displayed symptoms, or do they start the 7 days again from when B started showing symptoms? And so on if C & D begin to have symptoms?

As I understand it the 7 day testing starts for persons C & D on the day A tested positive & then resets on the day B tested positive.

Similar situation in our household, DD tested positive on Friday, both DH & I started daily testing, I tested + on Sunday, DH had to restart 7 day testing from then, DS tested + today, DH has had to reset 7 days testing from today.

Thank you. That was my thinking but I haven't been able to confirm it online. Tbh the whole thing is as clear as mud.