This is from the GeoExt quickstart:
- Download GeoExt from the downloads page.
- Download OpenLayers 2.10 or later.
- Download the latest Ext 3.x from the ExtJS website.
Place both unpacked libraries in a directory that is published by your web server.
That way you make them accessible from the web:
<script src="ext-3.3.1/adapter/ext/ext-base.js" type="text/javascript"></script>
<script src="ext-3.3.1/ext-all.js" type="text/javascript"></script>
<link rel="stylesheet" type="text/css" href="ext-3.3.1/resources/css/ext-all.css"></link>
<script src="OpenLayers/OpenLayers.js" type="text/javascript"></script>
<script src="GeoExt/lib/GeoExt.js" type="text/javascript"></script>
<link rel="stylesheet" type="text/css" href="GeoExt/resources/css/geoext-all-debug.css"></link>