How to enqueue the style using wp_enqueue_style()

I’m developing a theme. I added the codes (below) into the header.php. But I posted it into the WP theme repository, and it’s under review, and the reviewer informed me to enqueue the style with wp_enqueue_style()/ wp_enqueue_script(). But can’t understand how to implement it with the function. I’ve seen the directed wp_enqueue_style(); in Codex, but can’t understand how to put the whole bunch of codes with their conditions.

Site needs massive upgrade – how to proceed?

I have a former customer who, contrary to my recommendations, has not stayed on top of their WP upgrades. They now need to make the leap from 3.5.1 to 4.1.1 (or whatever is current at the moment). They used a fairly vanilla theme (might have even been Twenty Eleven), and not used too many plugins.

WPDB Insert or if exists Update

I’m not crazy familiar with WPDB or SQL in general but I have a custom table for my project and I’m trying to assign some metadata to it. What I’d “like” to happen is if a row exists, update it and if not insert it. I’ve read both Insert and Update in the WPDB Codex but neither really went into an “either or” situation. I thought i could work with update, so my code so far looks like this: