I want detect user browsers with .htaccess & redirect when user does not entered the site from cell phone
You can start here with an example.
# Rewrite requests from all user-agents except modern Internet Explorer, Firefox, Opera
RewriteCond %{HTTP_USER_AGENT} !^Mozilla/4\.[0-9]+\ \(compatible;\ MSIE\ [0-9.]+
RewriteCond %{HTTP_USER_AGENT} !^Mozilla/5\.0 \(([^;]+;\ )*[^;]+\)\ Gecko/2[0-9]{3}\ Firefox/[0-9.]+
RewriteCond %{HTTP_USER_AGENT} !^Opera/[0-9.]+
RewriteRule .* X.html [L]
Adjust as necessary.