bulgaria_mitko, lots of unhelpful folks here, sorry about that. My WhiteRussian skills are a bit rusty, but have a look at this page, it should have the default firewall.user settings:
https://dev.openwrt.org/browser/branche … r?rev=3319
On your router, you'll need to open an SSH connection (you mentioned you were using putty, this will work), from there you will need to edit the /etc/firewall.user file for the forwards you want done. The vi editor is built in, there are numerous guides on using this editor on the net.
The sample document above has three main sections, the first (Open port to WAN) opens ports to the router itself, for services that are handled by that device. The next section (Port forwarding) is for forwarding ports to other machines on your LAN. The last section is for setting up a DMZ, and that's a whole different topic, and is likely not what you're needing.
You may want to make a backup of this file on your router before making any changes, that way you can quickly revert if your changes cause problems. If you are still stuck, post the contents of your file and detail what changes you need, and we can figure it out.