Although I am not nearly the accomplished woodworker as some, I agree completely with the process described here. Cut down sheet goods to get workable sizes and finish sizing them by setting the fence or stop for consistent dimensions.
In the past, I would hand lay out the initial cut list, either using pad and pencil or a CAD program. A few months ago, I discovered an online app that performs this task well enough that I use it as an initial guide, to figure out if there are layouts that optimize the number of pieces I can get out of a sheet, be it a full sheet or what I have on hand. It allows designation of grain direction and whether to heed the grain, as well as individual sizes of sheets and type of material, quantities, etc.
I now use it regularly, as I said as an initial guide, using my judgement when it comes to actual cutting. It helps a lot in determining if I have enough sheet stock available. What I have not found is whether it allows for marking sheets for blemishes, such as knots or patches, that I want to avoid. That would be very nice, as, as careful as I try to be, I still find some showing up where I didn't want them.
There are a number of these online apps available and I have tried only this one, but like it. For now I use it on my PC. It is not available for iOS devices, but is for others, via Google Play. I have found one that is similar for iOS, but I've not used it yet, so will not comment further on it.