After inserting you'll need design correction and other things. I'm really sorry but we don't provide forum customization service in free support forum. The support forum is open for problem fixing and helping to use and manage forums not for custom codding. I'm really sorry but you may need some developer to help you customize your forum layout and design.

Also you should aks that developer to use update save way for any customization based on this documentation: https://wpforo.com/docs/root/forum-themes/theme-customization/

Hey where should insert this line of code. My coding skills are not that great.

Thanks in advance.

Call this function to display Current Login User with a ink to that user profile page:

<?php wpforo_member_link( WPF()->current_user ); ?>

Or just use WPF()->current_user array to get any data of current login user:

<?php echo WPF()->current_user; ?>

See image