Two ways to Insert your new store into your site
1. Just add the shortcode [WP_online_store] to your new page/post. I would advise adding the shortcode when in the 'Text' (HTML) page editor.
2. Create a new page/post and in the page editor (WYSIWYG) you will see a shopping cart icon just click it to add your store.
NOTE: If you using a third party WYSIWYG in WordPress (E.G.TinyMCE) the cart icon might not appear, so just use the shortcode.
If, after adding the shortcode to a published page, you still do not see any store on the front end of your site, then there may be a clash with the theme you are using (thsi happens occasionally, but not often). Try changing you theme to the standard twentytwelve which comes with wordpress to verify the store function.