So I have to make a dictionary in Java using binary trees, but I haven't figured out how I'm going to do this, if anyone could help that would be really appreciated!

not sure what your specific requirements are but i'll give it a shot.

i assume by dictionary you mean given a word, find its definitions. i assume you already have some sort of list/file/etc for all this data.

first store it all in memory in an array/arraylist/etc. then sort it. then build your BST from that sorted array

http://leetcode.com/2010/11/convert-sorted-array-into-balanced.html

you do this to build a height-balanced tree. if you just randomly add it, then you risk bad worst-cases (eg: linear search)