D-Link dwm 156 (A8) USB modem

Hello, this is my first message in the forum. I just installed openwrt to my tp-link tp mr3420 (v5) router and want to use my USB modem with it. Modem is a D-Link dwm 156, with hardware version A8.
Can someone please guide me, since I could not find much with Google searches?

As a starter: https://openwrt.org/docs/guide-user/network/wan/wwan/3gdongle