It's not tiking anymore

Leuga, assuming you're talking about the Apple Analog Watch in the device category, then given the age of the watch it's almost certainly a dead battery. According to the teardown, it uses a standard AG4 alkaline battery cell.

You open it up just like most analog watches, by prying open the rear cover. A plastic spacer comes out giving you easy access to the battery for replacement. All that is detailed in the teardown guide.

Apple Analog Watch Teardown - iFixit

Just follow it up through Step 6 and you should be good.