HOW DO YOU REMOVE LINKS FROM ALL IMAGES ON INDESIGN

If I'm understanding your question correctly, select all of the Graphic Fames on your page or spread with your Selection tool, and press the Select Content button in the Control panel. This will select the images contained in all the selected Frames. Press delete and the images are gone, but the fames remain.

See screenshot for location of the Select Content button.

all images linked and I have no idea how to effectively use this feature and delete and replace images.

All images have two parts—the image and a parent frame that holds it. If you use the Direct Selection tool (the white arrow in the Tools panel) and click on the image, the image is selected and it can be deleted along with its link reference in the Links panel.

With linked images, the preview is a low res proxy, which greatly improves performance, but the linked files have to travel with the InDesign document in order to be output at their full resolution (the link can't be listed as missing in the links panel). Links can be embedded from the Links panel’s flyout menu, and in that case they no longer have to travel with the document—but multiple embedded images can make the InDesign document perform poorly if they are too large.

You can’t just upload images, they need to live in the links folder.

if you don’t want an image, delete it, it will disappear from the links panel, if you want to replace it have that image saved in the links folder, and using the links panel choose re-link, and select the image from the links folder

If you mean you want to replace existing images – when you Place an image ensure that Replace Selected Item is checked.