Keywords are at the heart of every Google Search Ads Campaign. You have to make a lot of decisions surrounding keyword selection when setting up and managing a Google Ad Campaign.
One on the first questions is, "Should I target long-tail keywords with low search volume or only high search volume keywords?"
"What match type should you use? Is Broad Match only going to waste your money?"
Everyone has their own strategy when it comes to keywords. I can really only tell you what has worked well for me.
When I setup a Google Ad Campaign, I don't worry about search volume, only relevancy. I believe so long as a keyword is relevant, you should target it. This way you'll be able to track performance for that keyword more easily and make adjustments based on the performance.
If I find I'm not getting enough search volume after the initial setup and keyword selection, then I look into adding more keywords.
I don't set out to add every possible relevant keyword from day 1 when starting my Google Ad Campaign.
Keyword management is what I consider ongoing work. Every week, you add some keywords you might not be targeting yet and you add some negative keywords that you don't want to get clicks from anymore.
You can learn more about my system for choosing and managing keywords in Google Ads here in this other blog post.