A loop is what you want to create a perimeter around your model. Making the distance 10mm will starts the perimeter loops 10mm away from your model.
Brim is intended to extend the base of your model's first layer, so you can get better adhesion and prevent curling. You don't use a loop value, you use a width value as in your case 6mm wide. For the brim, the distance from the model should be 0mm, as you want it attached.
Enforcing support for xxx layers only make sense if your model doesn't have a flat bottom surface, or if you have overhangs at the bottom of your model but you don't want to turn on support for the rest. This setting seems to be effective only for the first 30-50 layers
As for the raft, it's probably there, under the first layer. The raft doesn't extend beyond the boundaries of the model, it's like a pattern infill under your model, and it's intended to elevate the first layer of your model above the print surface. Look at your gcode 1 layer at the time, and carefully watch the first 3 or 4 layers. It should start printing what appears to be infill, the raft, then after the first 2 layers, it will print a solid surface, which is your actual model's first layer.
Edit:
Here is an illustration to clarify the information above.
First image is of a 3 loop skirt only. The it's spaced away from the model by 3mm.
Image 2 is a brim. It's 6mm wide and the distance from the model is set to 0, however I just realized that the distance value is not relevant to the brim.
Image 3 shows the brim, along with a 2 layer raft. Notice that the brim is now attached to the raft, and it follows the raft's shape, not the model's.
Last image is the first layer of the model, going on top of the raft. This is actually layer 4. The raft is made up of 2 layers on top of a grid.
Another thing I found out myself is that the skirt and brim are not mutually exclusive, Slic3r will create a weird, merged combination of the two. The brim starts at the model edge and extends to the first loop of the skirt, then you gave the skirt, then you have another brim, attached to, and following the skirt outline.
Hope this helps
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