You could look at the json plugin by yann and see if that's something you could work with.
Alternately you could use the browser object to access the info.
First step is to get the json data into a variable. Options include:
* using the Ajax object to get a file added to the project or even from a web address.
* pasting it into a textbox when you run the game.
* creating a variable and pasting it as the initial value.
* using the set variable action and pasting it there. For this one you'll need to first replace all the " with ' and put a pair of quotes around it.
Ok, so you get the json data with one of those methods and put it in a variable, you then run this action:
Browser: run js "window.myjson=" & variable
Then barring any js errors you should be able to access any value in the json with something like:
Presentations is an array so the above accesses the first one and gets it's name. At least it should, unless I made some typo.