The lid has 4 small holes, I don't know if it is threaded and some watchmaker is needed. I try it with both ends of fine pliers and I can't open it. If someone tells me how to open the clock I am grateful, or if I have to buy a tool. Greetings and thanks.

Screw caps have 6 notches. If you have 4 it is only decoration. Look around the edge that should have an almost imperceptible tongue or none. If you have it, pry it with a knife or small spatula and you will feel it open. Once the battery has been replaced, place the cover in the same position it was and press it with your fingers. If you do not have that small tongue, perform the same procedure anywhere in the perimeter, preferably away from the time setting crown. regards