If you need it suddenly at night, you can finish in three steps; many users log in first on a phone linked to bKash or Nagad, then install the APK
First download the file, then allow unknown sources, finally open the app and log in to 999bd on Android 8+ phones; these steps usually take only a few minutes
1. Download the file
Download the APK from the support page or blog link; when the file goes to the phone's Downloads folder, the next step will be easy
2. Install
Grant the required permissions from security settings, then tap Install, and wait for the progress to finish on the screen
3. Log in to start
When installation finishes, open 999bd Login; if you have a previous account you'll go straight in, else start from the Register button