Solid Hardwood, Engineered and Laminate Flooring - need help measuring to begin installation

We're getting reading to install our floating engineered wood floor, but the room is slightly off-square. Can someone provide or direct me to easy to understand, step-by-step directions for measuring and making sure we start the first row straight?

Don't know if this is right, but just like suspended ceiling tiles, draw an X from corner to corner start at the X and work out ward. As an after thought mesure the lenght of the room in lots of spots mayybe 6 inches apart. Use the shortest mesurement and lay your plank across that, scribe the first board if needed, I think there is to be a 1/2 inch gap all around any way. I hope this gives you room for thought.

First I would determine which way the planks were to run in the room. Then, measure across each end wall which is perpendicular to the run. Find the center of each end wall and mark it. Snap a chalk line between these two points. This will establish dead center down the room in the direction of the planks. Now measure a plank and add 1/2 inch to that dimension. At the place along the wall where you find the longest distance between the wall and the previously applied chalk line, mark the dimension of the plank plus the one half inch. Measure the distance between this mark and the line in the center of the room. Now, go down the line in the center of the room and measure out the same dimension in several areas along the wall. Snap a chalk line and this is the reference line along which you will align your first row of planking. You will have to trim each plank to allow the 1/2 inch gap required between the edge of the plank and the wall because if the wall is truley not square, the only place you will fit a full plank is at the area where you marked the width plus 1/2 inch - all other planks down that wall will be narrower.
Hope I have't confused you too much - just sit down and think about it a awhile - not that difficult.