I was wondering how can I actually set up this isometric grid in illustrator? How can I use it on a layer so it doesn't interfere with my design?
This is a guess. You have drawn a blue grid for future use as drawing reference, there's no actual artwork.
Group the grid parts, rename the group as MyGrid and lock them in the layers panel. Making a separate layer is also a good idea. It's possible to be locked, too to keep it not selectable(nor movable). Snapping should work if the locked item is visible. If you want to prevent also snapping to your grid, make the grid group or layer invisible in the layers panel.
Moving to another layer:
- select the grid, cut it into the clipboard
- create a new layer in the layers panel
- select the new layer to active one in the layers panel
- paste in place (=Shift+Ctrl+V)
It's possible also to drag objects in the layers panel from a layer to another. That has a risk to drag it to an unwanted layer and to create unwanted sublayers, but that's undone with Ctrl+Z.,
There's no need to delete anything, your grid works as is. You do not free memory by deleting a part of it.
Save the empty drawing as a template.
If you're trying to create isometric drawings, a grid like this will probably not help you too much. You should to look into a technique called SSR (for Shear, Scale, Rotate). There are many tutorials to be found under that name. Here is one: