There was a knit along last spring or summer for the Tempting II sweater that is almost identical to this one, and designed by the same gal. You might learn some things by reading through that thread in the “Knitalong” folder. You’ll have to go back a few pages to find it, but there is a lot of help there.
*Place next 12 [14,16,18,20] sts on waste yarn, work across 60[66, 74, 82, 88] sts, place next 12 [14,16,18,20] sts on waste yarn, work to end of rnd. Set aside. Do not break yarn. How do I attach this waste yarn on to the stitches on the needle and am i suppose to break the yarn as i go across?
You don’t attach the waste yarn to the stitches you actually put the stitches on waste yarn, like you would put stitches on a stitch holder. The way I do it is to thread a nice long piece of some other yarn through a tapestry needle and then run the needle through the stitches purl wise and onto the yarn.
What you are doing is knitting the body in the round. Then you put 12-20 (depending on size) of the stitches of the body on each side of the sweater onto waste yarn. These will become the armpits of the sweater. Then you knit the sleeves in the round and do the same thing with the sleeve, you put 12-20 stitches on waste yarn where the underarm of the sleeves is. When you join the sleeves and body into one piece to form the beginning of the yoke you do not do anything with the stitches you put on the waste yarn. Picture them being right under your arms on each side, you later close that up, but for now do nothing with that part. The stitches on waste yarn from one sleeve and those on the waste yarn for one side of the body need to end up lined up with each other. Ditto with the other side.
*Place next 12 [14,16,18,20] sts on waste yarn, work across 60[66, 74, 82, 88] sts, place next 12 [14,16,18,20] sts on waste yarn, work to end of rnd. Set aside. Do not break yarn. How do I attach this waste yarn on to the stitches on the needle and am i suppose to break the yarn as i go across?
Back to this part. No, don’t break the yarn. Put the first underarm stitches onto a piece of yarn and then knit the next stitch just as you normally would pulling the gap closed between the last stitch you worked on the last round and this new stitch. Work across the front stitches, then place the other underarm stitches on yarn and knit the first stitch of the back pulling it up next to the last stitch from the front that you knit. Finish the round, and set it aside. You end up with the body stitches all on the circular needle and the stitches on the waste yarn kind of forming loops and a hole at each armpit.
Then you do the sleeves and have them ready to join by having the underarm stitches on yarn and the other stitches waiting on double pointed needles. The yarn is cut from the sleeves so that they are free pieces of sleeve not attached to anything (but on the needles still).
Now you are ready for this part:
*Join Sleeves to Body
NOTE: Read through this entire step before beginning.
Using circular needle and ball of yarn attached to body, and working in 2x2 rib as set, work across 40[46, 52, 58, 64] sts of one sleeve, work across 60[66, 74, 82, 88] sts of front of body, work across 40[46, 52, 58, 64] sts of second sleeve, work across 60[66, 74, 82, 88] sts of back of body.
There should now be 200[224, 252, 280, 304] sts on the circular needle, and the sleeves and body should be joined, ready for the yoke to be worked. At the underarms, the sts on waste yarn from the body and from the sleeves will be opposite each other. These sts will be joined later on.
The first thing you are going to do is to join one of the sleeves to the body. Hold the circular needle in your hands like you were ready to begin knitting a new round, and the working yarn ready to start knitting. Now pick up one of the sleeves that is on double pointed needles and hold it under the body part, positioned so that the top of the sleeve is up near the top of the body (the dp needle you are going to begin to work off of and the left end of the circular will be parallel to each other) and the stitches held on the yarn (for the sleeve underarm) are just to the right of the first dp needle you are going to knit from. You want to be holding everything so that the sleeve is going to go on the body right side up and so that you can begin knitting with the circular needle tip that you have in your right hand. You will be knitting the stitches from the double pointed needle onto the circular, adding the sleeve stitches to the body. Knit all the stitches off the first dp nd and then begin the next one, continue on until you have knitted all the sleeve stitches from the dp nds onto the same circular as the body.
Then knit across to the next sleeve and do the same thing. Knit the back stitches. Now you have all the body and sleeve stitches on the one circular, no other needles involved. Picture trying to put the sweater on at this point. Are the sleeves going off in the right directions? Hopefully they are, if not take them back off and try again. 
