It's possible to work the way you do, but with Lr it's a bit awkward, particularly if you start editing (developing) your images in Bridge.
You ask: " I'm hoping that I can add those (already organized) folders into Lr, but can't figure out how."
You have to import the images. Without importing nothing can happen in Lr.
So, open the Import Dialog. If it shows only the small window of the Import Dialog, click on the triangle in the bottom left corner, to expand the window.
On the left side you'll see the <Source> panel. navigate to the folder in question and click on it to select it. You will see all images in this folder in the main window of the Import Dialog.
Then in the top center of the Import Dialog select <Add>.
<Add> is for importing images that are already on the hard drive and you do not want to change their location.
<Move> is for importing images that are already on the hard drive and you do want to change their location.
<Copy> is for importing images from camera / memory card.
By selecting <Add> Lr will import the images in their present folder and will display the folder.
Your Bridge edits will also be imported because on import Lr reads the image file and the xmp-file where Bridge has stored the metadata of your edits.
But this is true only for import. Should you then decide for an image that has been imported in Lr to edit it in Bridge again, these edits would not automatically be visible in Lr. This is so because with imported images Lr stores all edits in its catalog, and does not display the metadata from the xmp-file where Bridge saves edits.
But you can make Lr read and display these additional Bridge-edits by doing a <read metadata from file>. But this is problematic because <reading metadata from file> will overwrite any Lr edits.
So you see that because of the fact that Lr works with its catalog while Bridge does not, editing images in Bridge and in Lr is a recipe for frustration. It can be done, but it's awkward and prone to mistakes.
Therefore I would suggest to bite the bullet and henceforth use Lr as your only editor. Import images from camera in Lr, do all your editing in Lr.
Since you are used to do edits in in Bridge Camera Raw, Lr will pose no big problems for you.
But if you don't want to let go of Bridge right away, I'd suggest you do at least one thing: After importing the images in Lr refrain from further editing these images in Bridge.