If any of this is unclear, go back and watch Module 10.1 again.
As you will have seen from the video, assessing your hand as weak, individual or game-forcing is simply a question of adding your points to what your partner has shown to see if you definitely have, might have or definitely don’t have 25 points between you
When your partner has opened a suit at the one level they will have 12-14 points the majority of the time so that should be the range you use to assess the strength of your hand for your first response. If they show more with their second bid, you can re-assess your combined point count at that stage. So 13+ is game-forcing, 11-12 is invitational and 6-10 is weak. With less than 6 your hand is very weak and should not be responding
When your partner has opened 1NT, showing 15-17, then 10 points will get you to 25 when they have a minimum hand, so that is game forcing, 9 will get you there when partner has either 16 or 17 so that is invitational, but 8 points calls for a bit of judgement as you will only have enough when partner is maximum. It’s considerably less likely that partner will have 17 than 15 points when they open 1NT. The best way to think about 8 point hands opposite a 1NT opening, therefore, is that a ‘good 8’ is invitational and a ‘bad 8’ is weak. A ‘good 8’ would have a five card minor suit (you will see in the next module that 5 card major suit holdings are treated differently opposite 1NT) and plenty of ‘intermediate’ cards, by which we mean 10s, 9s and 8s. Although these don’t contribute high card points, they are useful for taking tricks in no-trumps, especially in longer suits
So this hand, with its five diamonds and a good smattering of intermediates is a ‘good 8’ and should be treated as invitational when responding to 1NT.
Whereas this one, with no long suit and lots of small cards is a ‘bad 8’ and should be assessed as weak opposite a 1NT opening bid.