That's brilliant Lizi! Far better than my 1st ever attempt!
If you're stuck at what to do, try youtube. It's got some great tutorials on there & it's so much easier being able to see the person doing it rather than just following typed instructions
As for feathering. If you open up your pic, look down the sidebar on the left & there should be a tool that looks like a rectangle/square (can't remember!
) drawn in broken lines. If you right click on that it will bring up the circle one. Click on that & then a bar at the top should give you an option of feathering. Type in about 20 pixels (depending on how big your pic is really. You can try different sizes til you get it right) then click over the pic & drag until you get it the size you want. Then press copy & then paste it onto your siggy
HTH, i'm usually crap at explaining stuff online