There are three rules when determining what direction to install a plank floor.
When you open the front door it is inviting to have the planks running front to back showing you the way. They can also invite you further into the home. Used diagonal they could even direct you in a certain direction.
Install the flooring planks into the light. Maybe towards windows in the back of the home or other.
When subfloors are a bit uneven (most are at a bit), running into the light rather than across (side to side) to the light helps hide shadows, that can be caused by some ups and downs in the subfloor.
The long way. Think hallway or galley kitchen. Or an open floor plan running from one room into the next.
With glue down installations you have the option of turning the plank at a hallway or office doorway if necessary to get the feel and look you like. With floating floors you often need to stick to one direction in all areas unless a trim piece is added.
My Mother said “listen to everyone, and then do what you want”. So here are the rules, However if you like you can always throw one or all of them out.