Question for web chanllenge necessary file

Just want to know If I must download the necessary file(i.e. the source code) when I am playing the WEB challenge. In some challenge, it is too difficult without the source code, but on the other hand, it is kind of easy to solve the challenge if I downloaded and read the necessary file. So how can I balance this?

do they give the source code on hard challenges?

Yep´╝îmost of Web challenge give the source code in the necessary file.

Idk, if it is too easy you could do it without the source code if you can. There is probably no other way to make it harder.