As I can see in the code, ViewFinder does a case sensitive search for a template based on whatever you provide to the view() helper.
Pass Index to view() instead of index or change the template name from Index.php to index.php.
If your view renders correctly, but CSS file is not loaded, it means it's inaccessible to the browser. Files that are not returned via Laravel need to end up somewhere in /public folder so that web server can read them and return to the browser. You need to place them there manually or using some build toos (gulp, grunt, ...).
In your case, your bootstrap file must end up in public/bootstrap/css/ folder.
You could also fetch the bootstrap file from a CDN by using one of absolute URLs you can find here: http://www.bootstrapcdn.com/, e.g.:
<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" type="text/css" />