Watch this video from 3:47 for tips on using the gerund as an adjective:
And this video from 2:17 for more information on using the gerund as an adjective with the correct endings:
Honestly, talking about German grammar in an interesting voice is really hard! You don’t believe me? Try it with a friend! However, this guys does a great job of explaining what you need to know and giving you good tips. Give it a chance…and stay awake to gain the maximum benefit from these videos 😉
(PS) This is relatively advanced stuff, geared towards Higher and above. That doesn’t mean you shouldn’t try to understand it if you’re a beginner, it’s just a warning not to get disheartened if you don’t quite get it yet!