See right hand 1 and 2:
http://garywillis.com/pages/lessons/lessmain.html
Do the pattern in reverse i.e starting on the lowest string.
BTW, this exercice is not about doing 123212, 123123, 321321 or 2³½8°¾, it's about the muting. All you need to do afterwards is picking real music and make concious choice about which finger will play which note, like you would on the fretting hand. Soon enough, you won't think about it.