Go to downloads drag the zipped file to the card then open the file. Delete the instruction file and you should just have the .bin file left. (Other than DCIM)
Removable prop guards reinforce the motors, ( don't need to use the guards). On some cracks you might be able to drill a small hole at the ends of the crack. In metals this relieves some strain and stops cracks.
Depending where you live it can be up to 30*+-. There are maps that show what to add or subtract. Here in Michigan there are some wild variations in the UP because of the iron deposits!
I use a Galaxy tab A. Since the update I have no lag, never had an app crash and I can fly both batteries with no heat issues. Galaxy seems to be brighter than Apple screens.