The things in video are old. This old gw_hytera_mmdvm was build for FW 8.xx of HYTERA repeater and had some issues with the newer FW 9.xx.
There was another (but last) update of the gw_hytera_mmdvm last year with support for FW 9.xx. This requires a Pi with debian10 / buster. I am actively using this here with a RD985, my HYTERA runs with FW 9.xx. OE1KBC no longer develops this software. It is discontinued. But there is still another way to use this software. Look here: https://www.a23-wertheim.de/downloads/dmr/dmrgateway-2/file/35-dmrgateway-image-a23-06092018-zipThis is a finished image for the Pi. It contains the last gw_hytera_mmdvm.
But there will soon be an alternative. Look here: https://github.com/OK-DMR/Hytera_Homebrew_Bridge
It's beta and not finished yet, but under active development.
73 Heiko, DL1BZ