This is how I replaced the battery on my Casio 1572 A168 watch.
1- Undo the 4 screws to remove the back cover. Note the correct orientation for reassembly by observing the writing.
2- Gently pry out the mechanism.
3- Undo the 6 clips round the circumference of the mechanism with a pin or watchmakers screwdriver. The top half should come loose. There is also a 7th clip which can be more easily unclipped from underneath. Replace the battery.
4- Note the correct position of the small spring. This spring is necessary to make the watch speaker work.
5- Note from the picture the correct position of the special contact which connects with the lower board. If this does not connect properly then the display will disappear.
6- With the battery in place, the watch display should work properly. If there is a problem try connecting the two all clear contacts with a screwdriver, paper clip or small piece of wire to reset the watch.
7- Reassemble the watch and make sure the rubber seal is in place. The seal on my watch was slightly deformed so I used a very small amount of silicone sealant on the tip of a screwdriver to tack it down properly.
8- Put on the back cover being careful not to overtighten the 4 screws and damage the threads. The cover needs to be positioned correctly and not 180 degrees in reverse so the spring will connect with the correct place. When you look at the front and back of the watch the writing should be the same way round.
*Looking at the picture it might also be possible to replace the battery by removing just the one clip that is closer to the spring. However I found that that clip is more easily undone from underneath, so I preferred to do a more complete dismantling. This also gives more freedom to reposition the battery.