"i need to know how to make sure that all my data that is on the old drive will now fall onto the new one."

This is something you have to do when you save your files to the new drive. Some have asked how to make Windows do it automatically and even with one idea, it proves that Windows does not do this. So we get to do the work.

Here's a thought. Why not use SyncBack to keep a spare copy on your new drive?