For service personnel based overseas, you will need to switch your app store region to Singapore to download the app. For Apple users, you will need to open 'Settings' on your device, tap your name, then 'Media & Purchases', tap 'View Account', then 'Country/Region and choose 'Change Country or Region', and select 'Singapore'. For Android users, you will need to open the Google Play Store app, tap 'Menu' then 'Account', find 'Country and Profiles' and switch to 'Singapore'. Alternatively, you may access the Leave and Claims module via OneNS website (www.ns.gov.sg.