Firstly think of the fields you like to use on your new table. Of course there's the ID, thread ID and the question. You should also put a field for enable/disable.
I made a similar hack and you can look at it to see what hooks you need to use.
https://vborg.vbsupport.ru/showthread.php?t=128587
I suggest creating another table that holds the user's ID, the question ID and their answer.
If you know how to use 'LEFT JOIN' then you do not need to make a field for "thread ID" but since you do not know that much you should add "thread ID".