If the images are already "where you want them" then you must be using Lightroom Classic, which stores images locally and utilizes a local catalog. If that is the case, the process of importing is the process of adding the images to the Lightroom catalog so that Lightroom knows where the images are located and can subsequently keep track of all the work performed on those images. The catalog is actually the only file Lightroom Classic opens, and is critical to the proper and smooth functioning of the program. Without the catalog, and without importing images to the catalog, you simply cannot work with images in Lightroom.
One of the import options is to Add Images, which will add them from their current location. So, in that case, the import process is simply a process of adding the images to the catalog which is a database, and that is what allows Lightroom to keep track of everything you do with the images. Since Lightroom is a parametric editor, all of the adjustments you make to your images are stored in the catalog. The images are left in their pristine state, untouched.
Just to expand on Jim's answer, when you start the import process and select the specific folder in the source panel on the left, there are 4 import "types" listed horizontally across the top of the centre panel. The first 3 (Copy as DNG, Copy, Move) will all require you to set a destination folder for the images so that they can be copied or moved in accordance with the selection. These are more typically used when importing images directly from camera card (so you could very easily bypass your initial manual copy of the images to the hard drive, and have Lightroom do that for you). The final option, Add, should be automatically selected if you are importing from an existing hard drive (as you would be doing in the situation you describe), but just check to make sure.