Upload the albumize folder to the /wp-content/plugins/ directory
Activate the plugin through the 'Plugins' menu in WordPress
Create a page that will function as your album and place the [albumize] shortcode in it.
Create child pages of your album page and place your galleries in them.
(Optional) Create a brief description of your gallery by using an "alb_blurb" custom field key and the description in the value.
(Optional) Select the gallery cover for the album by using an "alb_cover" custom field key and the number of the picture in the gallery (e.g. 5, 13, etc) for the value. The first picture in the gallery will be used by default.