I don’t understand.
How do I work only knit stitches on the right side and purl stitches on the wrong side ‘through the back loop’? What does that mean?
The instructions go on to say:
(WS) K1, [p1, k1] 8 times
How on earth do I do this!
Thankyou for your time 
This is the pattern: http://us.macmillan.com/uploadedFiles/custompagecontents/titles/75%20Birds,%20Butterflies%20and%20Little%20Beasts%20to%20Knit%20and%20Crochet.pdf
For this WS row, alternate k1 p1 across the row but work the purl sts through the back loop (tbl)
For the RS row, alternate p1 k1 across the row but work the knit sts through the back loop.
There’s a video of tbl on the Glossary tab at the top of this page. It will tighten up the st and twist it in each case.
Oh, I see! I get it! Thankyou very much.
One last question.
I don’t understand these instructions:
(k1tbl, k1) in next st, then insert tip of left-needle behind the vertical strand that runs down between the 2 sts just made and k this tbl to make 3rd st of group.
I understand (k1tbl, k1) but what is this vertical strand? I have identified one, but I don’t exactly understand how I am upposed to ktbl with this ‘vertical strand’. Do these instructions insinuate that I will end up with 3 stitches after performing this? (One stitch from the k1tbl, one from the k1 and one from the ktbl with this ‘vertical strand’)?
I think the simplest thing is to knit again into the back loop of the original st before you drop it off the needle. And yes, you’ll have 3sts from the original one sr.
I’m sure you know how to knit through the back loop. Purling through the back loop is similar. On a ktbl, you will insert your needle through the back of the stitch from right to left. On the ptbl, you will insert the right needle through the back loop from left to right. The easiest way to do this is to position your right needle with the point almost straight up when you insert it into the stitch. Hold your left needle with the tip up at a 45 degree angle. It takes a bit of gymnastics, but it can be done. Your yarn will be in back of your work while you’re doing this Ptbl.
Eastern European knitters like me do our purl stitches this way all the time. We become conditioned to it and it becomes second nature. However, this is an unnatural position for Continental and English style knitters. Take frequent breaks from your work to relieve the stress on your wrists. If your wrists get sore, my favorite remedy is Aspercreme topical pain relieving ointment. You may have no problem with wrist pain, but you should be aware that it can happen.
(k1tbl, k1) in next st, then insert tip of left-needle behind the vertical strand that runs down between the 2 sts just made and k this tbl to make 3rd st of group.
salmonmac’s idea is certainly the easier thing to do. I don’t remember ever coming across this direction before so had to try it out. It took a while for me to decide what the vertical strand was (and I looked everywhere for it :lol: ) but I think I found it. Keeping the right side facing you, after you ktbl and k the stitch and still keeping the original st on the LHN, pull down slightly on the work under the RHN and you will see a strand running slightly off to the right and down to the st below \wise. There seem to be more than one really, but you want to insert the left needle left to right behind the topmost strand. Now you have a new “loop” on that LHN, and you want to knit that little loop as though it were a regular st loop, behind the LHN (or tbl). Now let the original stitch loop come off the LHN. After you finish this rather awkward maneuver you may need to pull around on it a little so that all the new loops settle into the places they need to be, I found I needed to. There are 3.
It is quite a bit harder and looks only a little different than what salmonmac suggested. Try the two out on a swatch and see if you think it matters that much.