If im not mistaken I use Ip Tables to do this?

I've researched a little and I just wanted to find out some answers:

iptables –t nat –A PREROUTING –p udp 50* –j DNAT –-to
iptables –-table nat –-append POSTROUTING –-out-interface eth0 –j MASQUERADE

In order to make the forwarding work, can I just run these commands? Can I specify the port by just adding the number *'d above? Do I need to ARP the router? Set up MiTM between me and router?

I saw a simliar thread with these commands but it was quite old and I didnt want to revive an old thread. Also it didnt quite answer those questions.

Thank you in advance