Here is the code you can use to insert a search box on all your other pages than the main search page.
If people search using this, it will open your search page showing search results immediately.
You may need to change the "action" URL depending on how you structure your website.
Note: You can remove this section from your main search page.
<form action="recherches-in.html" method="get">
<input type="text" name="search_p" value="example"></input>
<input type="submit" value="Search"></input>