How do I get rid of these edges? I've tried the Join Tool. I've tried to highlight them with the white and the black arrow and then Object>Path>Join.
At this point I don't know what to google for, since everytime I search for a solution only the same suggestions come up, which I've tried.
Thanks
You can only join the end points of open paths so joining in this case won't work.
If your strokes are the same weight, snap the end point of the open path to the other path (turn on smart guides to help), and set the end cap of the stroke to a rounded cap.
If your strokes are different weights there isn't much you can do (automatically anyway). You have two options.
Outline your stroke. You can then manually edit the resulting paths or use a pathfinder 'Divide' and delete the parts to don't need. This is a destructive process though, so you won't easily be able to edit the path or stroke weight anymore.
Use masks to hide the overlapping areas you don't need. This can be an actual clipping mask or sometimes you can use the fill of another layer higher in the layer order—this depends on the situation though. Extend the open path slightly past the other path to avoid the gaps on the inside edge. This is the better option as your strokes remain intact.
