This 4 minute video provides an overview configuring the HTTPS Remote Access Portal (Mobile Access Blade) on Check Point Security Gateways to publish web based applications.
Keep in mind that HTTPS Remote Access Portal based solutions are intended for short term sessions allowing nomadic users 'to check something quickly on the central application'. For long term remote access you want for sure look into IPSec VPN Remote Access Solutions.
The authentication is based on username/password to keep the scenario simple.
There are some troubleshooting tips related to DNS settings and relevant web application object configurations.
Enjoy 😀