When i turned DrayTek Vigor 2925 on and connected it to the WAN uplink and LAN cable to the computer, accessed entered login "admin" password "admin" i seen german language.
WAN port looked unused and there was no internet connectivity. Here is what helped:

I have used my old router to download new firmware from https://www.draytek.co.uk/support/downloads/vigor-2925
and extracted the .zip archive. Went again to Vigor2925 web interface Systemmanagement > Firmware aktualisieren >
Selected firmware file from extracted archive with extension .all (this one will overwrite all settings and configuraton presently on the router)

After router restart everything is in english 👍. So i go to WAN > Internet Access > and set WAN "Access mode" as "Static or Dynamic IP". Then "Details page" > Static or Dynamic IP > tick to "enable" and tick "Obtain an IP address automatically". Internet started working when the router booted up.