I am obliged to put the scripts in /usr/lib/cgi-bin ???
No you're not, but it's better to stick with your distro's defaults.
how to redirect link to /var/www/cgi-bin and for user count like ~bela/ ?
You can change the relevant entry in apache config file(s) to read:
ScriptAlias /cgi-bin/ /var/www/cgi-bin/
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Allow from all
but I don't think it's a good idea, as /var/www is the default docroot, so the cgi-bin will be a subdirectory of that.
I don't understand what you mean by "for user count like ~bela/", so please clarify