Hello all, this site is just fantastic, so many wise words of wisdom, so I turn to you all to ask for help once again.
I’m very new to knitting, and thought I’d give making a baby’s cardigan a go to practice some new techniques.
Im not at the stage where I have sewn the shoulder seems onto the back piece of the cardigan (no sleeve attached yet). Now I’m moving onto the collar.
I need to pick up new stitches along the sides…this bit is fine. But, along the back, I have stitches left on a stitch holder, so I need to go from; picking up new stitches, transferring stitches, then back to picking up new stitches.
Im not too sure how to go about this, for example, do I pick up new stitches, some how cut the thread I’m using, transfer the back stitches across onto the needle, then when I get back to picking up stitches on the other side, do I start the thread again, or do I just carry the thread across ?
Hopefully that all made sense. I’m not sure why my pattern told me to hold stitches on a holder, for the back bit, as opposed to just picking up new stitches all the way across : /
Many thanks in advance to anyone who can help displace my utter confusion !!! 
Some patterns have you bind off the neck sts and some have them held on holders. The collar will work either way.
Start picking up sts at the right front (right front when worn). When you get to the holder, you can knit the held sts directly off the holder or transfer the sts to another needle and knit them onto the working needle (the one with the right front picked up sts).
After knitting the held sts, the working yarn is at the tip of the right needle, ready to continue picking up sts along the left front.
No need to carry the yarn across or cut the yarn.

Hello,
Thanks ever so much for taking the time to get back to me, I really appreciate your help !!
I tried to do what you suggested as best I understood, however I’m left with this bit of wool that on the wrong side loops from one end to the other (I’ve done a very rough diagram in a picture which hopefully has attached to this message), but I don’t know if this is meant to happen (I’m going to go with ‘no’) and not sure what I should have done instead.
If you can see where I’ve gone wrong and how I should have proceeded, I’d really appreciate if you could let me know, just so I can hopefully avoid this same mistake in future.
Again, big thanks for your help. 
So you pick up sts along the right front up to the stitches on the holder. When you get to those sts, don’t transfer them to the needle, knit them off the holder onto the right needle. That way you avoid a long loop of yarn across the back of the neck.
Or did you knit the held sts and still have the loop of yarn?
no, I didn’t knit anything, just created new stitches along the right and left sides, and for the back where the stitches were on the holder, just transferred them to a separate needle then put them onto my main knitting needle.
I think Im confused, because, if I’m just picking up stitches along the sides, but knitting those on the holder, will this not make it uneven when I properly start knitting the next row? by this I mean, I’d be knitting the picked up stitches for the first time, but then when I get to those already knitted from the holder, would I not be then almost knitting a second row just on those stitches ? I’m sorry if I’m sounding so dumb 
Either way, I guess I’m just gong to have to keep practising and hopefully see it make sense by doing it.
Always, thanks again for your kind help and input 
It’s not going to be substantially uneven if you pick up (it’s often referred to as “pick up and knit”) at the sides and knit the back holder. Even if it were, it would be by small fractions of an inch, just as front shaping is often off by an unnoticeable row.
I’ve also worked patterns which add short rows at the back of the collar to increase the height there. So don’t be concerned about a difference in height.
Knitting across the holder sts is exactly what the instructions are telling you to do.
This is a good question which often comes up in one form or another. I can’t begin to describe what I did with these instructions when I started knitting sweaters. Aiee, what a mess!