I am puzzled by this question: How can judges make law?
(I'll focus conceptually on giving you some clarity and not on giving you an ace answer of how judges make law)
Firstly, by their interpretation of the law. This one might be a little bit "Ohhhh, but are they realllllllly MAKING law, or just interpreting it?" - I think both in theory and practice the judges are making the law. As it suggests, this is where there is already a statute, and in the judge's interpretation of the words (or perhaps even the intentions) of the parliamentary law-makers can create a 'new' law. My very favourite case example is the 'studded belt case' or Deing V Tarola. Police charged a man in a McDonald's (totally irrelevant, I just think it's funny that it happened in Macca's) who was wearing a studded belt with spikes coming off it that could probably do some damage. The legislation at the time defined 'weapon' as something that could do harm, which provided a very broad interpretation of what a weapon was. The court ruled that a weapon should be defined by the user's intention to use the item as a weapon. So the law effectively changed through the court's decision. If the law is changed, it is fitting that we can refer to the first law as Law A, and the second law as Law B. If we accept that two different laws have come from the one statute, we must ask the question "but who made the second law?" The answer has to be courts.
**If you aren't convinced there were two laws after the decision, consider a builder with a hammer on his belt walking back to a building site. Under Law A, he could possibly be charged with a weapon. Under Law B, he wouldn't be, because his intentions are not to bash someone's knees in, rather hammer some nails back on the building site.
Judge's also make laws through their decision on cases in which there is no relevant legislation. This is done through their reasons for their decisions. (What follows is heavily based off of a real world case, however I don't know the details etc so we'll just talk hypothetically) -> When camera phones came out, there were obviously no laws surrounding the immoral use of mobile phones. Let's say someone took an 'upskirt' photo using their mobile of a woman walking down the street, and the woman took the man/woman who took the photo to court. Without a relevant law to decide on, the judge is effectively made redundant, right? Wrong! Because a judge can make a law here and say "Nah, upskirting is pretty dog, I'm going to say the plaintiff wins, here is the reason for my decision". If parliament then doesn't recognise the need for legislative law and it happens again, the next court can go "oh, it seems a previous court has already made a law surrounding cases like this. The provided a reason for their decision. I agree/am forced to agree with that judge. The plaintiff wins". This is a very layman's introduction to the doctrine of precedent.
So: Through interpreting statutes. Through making decisions in cases where there is no relevant statute.
Does that fix your conundrum?