Each of your Collections contain Photo Sets, which in turn contain individual images. You would create a Collection for each event and use Sets for easy categorization. For example, the Collection “Jessie & Ryan's Wedding Day” could contain Sets such as "Getting Ready", “Ceremony”, “Reception”, and "Portraits".
To create a new Collection, go to the Client Gallery tab, and click on +New Collection.
Once you've created a Collection, you can upload your photos by clicking on +Add Photos. Use the +Add Set button to create additional Sets for the Collection and easily organize your images.
By default, every single Pixieset Collection will be created with a Highlights Set. You can upload all of your images to this Set, and then organize them, or you can create your Sets first, and upload to each Set as you go!