Add navigation arrows and an iterative pager (and category total) to your WooCommerce single product pages.
Since I haven't found a ready-made solution (i.e. plugin) to show a counter / pager for the WooCommerce single product pages (along with the obligatory nav arrows), I thought I'd share my solution.
This snippet goes wherever you want in the 'content-single-product.php' template file of WooCommerce, after you've ideally copied it in the respective folder ('woocommerce') of your child theme.
Hopefully the comments will shed some light on what's going on, so that you can adapt it to your needs.