Here is a copy/paste of my original reply on how I learned to do blanket stitches on the serger that you seem to be having a problem accessing......hope this helps.
The way we made a BEAUTIFUL blanket stitch, if I can explain......that's the best part about a class, you actually SEE it done......first get some Solvey type stabilizer (med to heavy) and cut into about 3/4" strips. I use medium weight. Set your serger up (remove right needle) to left needle - wooly nylon, lower looper - cotton, Differential-normal, stitch length 5, stitch width 7, tension-left needle 0, lower looper 7. These are the settings I start with to run a test before fiddling, your machine may have different settings but this should give you a bit of an idea. Lay the stabilizer strip on top of the edge fabric as you sew through the serger (using the cutting blade, don't roll it). When you have finished hold the fabric close to the serged seam with your right hand and pull the stabilizer (should be on top) firmly with your left hand. This will pull the threads about to make a blanket stitch that is very nice looking. I have used contrasting wooly nylon and cotton thread to match the fleece. Then you can wash or do whatever method you choose to remove the water soluble stabilizer. Tear away is a PITA to remove unless you are into tedious tweezer work and if you are using fleece I'd give a test run if you try Heat-Away
Like I said, those are the settings I use on my Huskylock 905, your mileage may vary but the technique would be pretty much the same.
Val