I had the same problem at first. And you motivation gets really low because of it.
This is what I did:
At some sites you can just see the solution for a challenge. Whenever I couldn't pass one I would look at the solution to learn to understand. And that really helped me. Look functions up that are used in that solution, so in the futher you know what to use.

What I did for this site, I look at the problem. And then figured out what I was suppose to do, like get the first char of an string. And then replace it. If I didn't know how to do this I would search it online 'replace first char of string php'.
Look up different solutions, and use what you think is best. After you submitted your code, look at the solution other members used on that kata. Try to understand what they did with their code, and if you don't understand just ask them. I'm sure they wouldn't mind.

I used this and still do to learn, and it helps! It's okay as long as you understand what you're writing and know how to use it in different situations or when to use it. Just never copy and paste..