Search for the site where you have downloaded the app.
One thing to keep in mind is to visit the site from time to time to know if any new version is available or not, or else you will get a notification when the new update will be launched.
If the update is available move forward to download the APK file.
The file will be downloaded in the device file manager section. Locate it and tap on it to start the installation process.
The new update will be launched after that and all the data from the previous version will be backed up and restored.
