Working the final loop of the first half of the row:
Insert the hook under the last vertical loop and the loop behind it(arrow points to these 2 loops), YO, and pull through a loop.
I find this gives the edge a more finished look, makes it as thick as the rest of the fabric,
and provides 2 loops to work an edge into.

Bind Off at Beginning of Row

Pull a loop through the 2nd vertical loop and the loop on the hook.
Pull a loop through the next vertical loop
and the loop on the hook. Work across. (This is really just slip stitch bind off)

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Bind Off at End of Row

With a separate length of yarn pull a loop through the last vertical loop
of the short row. (See arrow) Continue with bind off in normal manner.

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Extending Second Half of the Row

At the end of the second half of the row continue the (new foundation) chain the needed number of new chains.
YO, pull up loop in 2nd chain from hook and across,
pull up loop in 1st vertical loop of main fabric (see arrow) and across.
Work second half of row in normal manner.

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Extending First half of the Row

At the end of the first half of the row, add the needed number of new loops by using a cast-on.
Each loop will be formed by giving the supply yarn a full twist to the right
and then placing the loop just formed over the hook.
Second half of the row is worked in the normal manner.

Single pointed arrow points to the previous extension of row using the cast-on.
The cast-on is similar in appearance to the usual starting chain.
Double pointed arrow point to the last cast-on. It has been left loosely done to show the twist to the right.