When you decide to 
install hardwood flooring the first consideration is whether the floor supporting it is strong enough. If there is movement when you walk on it you 
may want to add another layer of plywood (and glue the layers together), for strength.
In this case the floor joists were undersized, however there was a full width 1 1/2″ cedar floor in place already. Considering that this 1″ beech (very hard), flooring would be glued to the floor beneath, it should be more than strong enough as long as we ran the flooring perpendicular.
We always start with a clean chalk line and in this case we would be fitting a threshold to the entrance door later, so we trimmed off the lower part of the groove to
make it easier to fit later.
The first couple of rows get surface nailed typically… set the nails well below the surface though, and make sure the first board remains aligned to the chalk line.
Planning for full boards along obstructions is something that you will find only experienced carpenters like Nick Vanegmond doing.
You will always start with the straightest boards, and alternate the width. This floor has 3″, 5″ and 7″ boards. For the boards to remain tight you 
have to use the smaller boards to split the inconsistencies. End cuts all have to be trimmed off about 5-7″ for straight from the mill products like
these.
Every board is glued to prevent squeaks and for added strength and durability.
A cut off plank is used to bump the flooring into place. Trim off the tongue of the block leaving the groove face… this way you don’t cause splinters that will obstruct the flooring from laying flat.
