First of all, the kfb is also called a bar increase, and it does not lean right or left. Also, sorry, I didn't see your additional questions until just now. I'll try to help you out with the shape armholes part now. How did the rest of it go??
Cast off 4 stitches at the beginning of next two rows. If you are unfamiliar with how to cast off, there are videos here. If you are casting off (also known as binding off) stitches on a right side row (knit row) you will use the basic knit bind-off, and if you are casting off on the wrong side row you will use the basic purl bind-off.
Dec 1 st at each end of next 7 rows and 5 foll alt rows ( 68 )
Decrease 1 stitch at end end of next 7 rows, you can decrease using K2tog on the right side rows and P2tog on the wrong side rows, videos for each can be found in the 'Abbreviations Explained' tab at the top of this page. It is a good idea to do the decreases one or two stitches in from the edges because it makes things easier for seaming. So, for example, you could knit the first stitch of a right side row, then K2tog, knit until 3 stitches remain, K2tog, then knit the last stitch.
Now, the....and 5 foll alt rows. That just means every other row, 5 times. So if the 7 rows that you just worked were rows 1-7, after that you will decrease 1 stitch at the end of rows 9, 11, 13, 15, 17. And the ( 68 ) in brackets means that after all those decrease rows you should be left with 68 stitches.
Hope this helps!