Hi,

Just navigate to wp-admin and Menus: wp-admin/nav-menus.php.

Choose wpforumNavigation and translate links: 

https://ctrlv.cz/z5k7

https://ctrlv.cz/eWJ3

The top main menu can be managed and translated using Glados' instruction, but if you need to translate the subMenu of profile page you should do that using one of this method:

1. Using wpForo quick-translation - navigate to Forums > Phrases admin page, separately search for these words: profile, account, activity, subscriptions. Edit those one by one and insert your translation.

2. Using wpForo POT file located in /wpforo/wpf-languages/ directory. You can translate whole wpForo using this method with PoEdit. More info:

http://wplang.org/translate-theme-plugin/
https://www.youtube.com/watch?v=5r1yZ1t2378

Thanks, I've been able to get everything properly translated now 🙂 .