Hi,

I admit to knowing virtually nothing about routing!

my company has had a 50mb connection put in terminated by a cisco router.

I want to temporarily use a vigor 2830 to sit between the cisco and the local area network, but am struggling to configure the 2830

I assume I can use port 1 as the local connection , using 192.168.1.254 etc, and want to use port 2 to connect to the cisco

I have been provided with the lan ranges, gateway ip, lan ip, and dns etc

anyone who could point me in the right direction?

You will need to stick the 2830 on the WAN Port (static IP mode) and assign that an address on the same subnet as the Cisco then the give it the CISCO's ip address as the default gateway.
IF the cisco is purely routing then that will be it but if depends what the Cisco is doing in the 1st place and whether its subnet is an external one.
This is generally how you would set up leased line connections etc.
The line is terminated by the router (cisco, Juniper whatever) then your router/firewall (2830, 2860, 2960 3900...) sits between the router and the LAN and does the NAT