Welcome to the forum! There have already been some great links given, but I thought I'd add a little to what has already been said. First off, it's nice to see that your snake is now in a caring environment.

Ball pythons can go quite long without eating, but much depends on the weight, size and age of the snake. Six months isn't too long and force feeding is probably premature at this point. The best thing you can do is to provide a nice envirnoment per the caresheets, then leave the snake alone for a couple of weeks. If everything is set up okay, you might find that your snake will eat as soon as you offer him a meal. A live mouse would probably be your best bet initially.

One more thing, you mentioned that you will be taking your snake to the vet. If at all possible, try and take him to a vet that specializes in reptiles. Good luck!!