Maybe start by defining 'slider puzzle'?  Maybe search online for examples of such things?  Even if these are written in different languages they might give you an idea of how to implement them in Processing.

...and maybe organise your time better and give yourself more time to do homework; because this sort of last-minute "Plz HELP!!!" question, with no indication that you've made any effort whatsoever - or what your level of ability is ("new to processing" doesn't tell us about any experience you might have with other languages*) - rarely gets much sympathy :/

* If I've correctly understood what you mean by 'slider puzzle' then it's not a particularly trivial project and I wouldn't expect a novice programmer to be given it as an assignment.

" i dont even know where to start" " I have been working on it for 2 weeks"
So for 2 weeks, you still haven't even started? I suppose no. So what about showing the current state of your work (don't be shy! ) so we can see together how to improve it?

I was intrigued by your situation and thought I would try to help. I searched for slider puzzle c code and found this:

If nothing else that C code demonstrates the potential complexity of the problem :)
The good news is that I doubt you're expected to produce anything quite so comprehensive...

The first thing to consider is how are you going to represent the tiles within the code?  A 2d array of ints with values counting up from 0 would seem a reasonable choice (though in fact in the first instance you'd want them in a random order) as it should be easy to use this later to check if they're all positioned correctly.  You'll then need to draw a grid displaying the values from your array.  Next you'll need to figure out which tile is under the mouse when it's clicked and check whether there is an empty space next to it (and if there is, swap them round).  Finally each time a swap occurs you'll need to check the values in the array to see if the puzzle is complete.

When broken down into these stages it seems a little less unreasonable for a novice, albeit only for one who has been paying attention and understood the concepts that have been covered so far in their class. Of the above the trickiest part is likely to be checking for a blank tile next to the tile that has been clicked (note you'll need to think of a way to represent the blank tile within the array - perhaps just give it a value of -1).

I'm not posting any code, but maybe this gives you some idea of where to start.  If you get stuck post your code ;)

Good luck!

We may have the same project since my teacher gave me that same link as an example. I'm also kinda confused about this whole thing as well, however. This is my first time learning anything anywhere close to this, so I've been pretty lost throughout most of these projects, but I would suggest google and hopefully asking someone on here to explain to a specific problem you are having. I would suggest starting by declaring the ints you know you will need. If you have instructions from the professor, read them over as many times as you can and break it down. If I figure anything out, I will try to help you as best I can...but all I can say is good luck.

I decided to be a hero (or a poor excuse for one) and posted my framework for the code on another discussion. I hope it helps. As I said before, I think we're all in the same class so lets help each other out!