Installing hardwood flooring in a simple rectangular room makes sense: start at one end and work your way to the other end. What do you do when the room is an unusual shape - similar to a "H"? If you're supposed to be nailing into the tongue side of the planks, what do you do when you reach the point where the layout back tracks on itself, leaving the groove side exposed for nailing? Thank you for your help.

Where you have to turn around, put a temporary support (generally called a "false wall") along your straight line along the floor. This is usually a strip of plywood screwed to the sub-floor and lay the floor as you normally would, with the groove edge of the line up against the plywood support.
Then remove this plywood, insert a piece of 1/4 inch by 1/2 inch material into the now exposed groove of the board and nail it in the same fashion, as though it were the tongue of the board. You now have, essentially created a board with two tongues, nailed on both edges. Continue the installation conventionally.
I usually just rip some scrap stock to make this spline, although they are available at some hardwood outlets.

Hope this is clear, its early morning here, so brain is only partially functional until second cup of coffee kicks in.

Thank you, Dennis, for the advice. Should the false wall be the starting point of the job or should I follow this procedure when I get to the transition area?

Also should the new tongue that I create be cut from the same wood species as the flooring?

Thanks again.

Start the install conventionally, and when you reach the area where you will have to turn around, project the line of flooring through the space where you will need to reverse your install direction. This is where you will need to put up your "false wall"
The spline should be the same or alike type of wood but not all that critical. The important thing is that it fits snugly into the two grooves and is nailed in place the same as the tongue on the other edge.

Thanks again, Dennis. This is very helpful!