You can register for testing the game by following the link
After signing up, as soon as the test of the game begins in your region, the automatic download of the game client will begin.
Please do not create support tickets questioning about the timing of the start of the test in a particular region. As soon as the game becomes available, you will receive a notification about this if you have singed up for the test.
You can also download the apk file with the latest version of the game from the game website (only for Android devices): https://wtmobile.com/ .
Before installing the apk, make sure your device meets the minimum system requirements for the game: System requirements for War Thunder Mobile
Please note that the localization of the game depends on a region in which the game is being tested.