Afghan border

[Pegatha1]

I have knitted a 12 block afghan and joined the blocks. The instructions state to add upper, lower and side borders.
I have done the upper and am finishing the lower before I start the sides but cannot figure out how the borders will meet at four corners.
I have not knitted for about forty years and then only knew basics. I have tackled this intermediate project and am satisfied that it is OK even with
varied knitting and errors.
I hope you can help.
The afghan is from Better Homes and Gardens Kit Lion Brand Multi Square Throw- October or November 2005
Thank Youn
Peggy Taylor

[Ingrid]

How did you work the ends? If they're in line with the sides, then have your side borders go all the way from one end to the other, including being a border of the end borders. Does that sound understandable?

[Pegatha1]

Thank You.
I will try to complete in this manner but will let you know if this does not work.
Peg T.