If you are using the Amit IDG761 4G router and need remote access to the router web management interface then the following support video will provide clear guidance on how to configure the IDG761 router.
The support video first provides information about configuring the APN settings for your Fixed IP SIM Card so the router can connect and be accessed via the Internet using the IP address allocated to the Fixed IP SIM.
The video then advises how to enable the router web admin remote access via the firewall settings and shows how you can allocate the remote admin port.
NB : you will need to ensure that you are using a Fixed IP SIM Card with your Amit IDG761 4G Router if you intend to remotely access the router. This also applies if you intend to use port forwarding within your IDG761 to connect to devices on the LAN eg. CCTV NVR. Using a standard mobile date 4G SIM Card will not allow remote access to the router.