Hey balsed,

The Transition Builder is used for creating slide transitions, it cannot be used for layers. 
The options to set up layer animations can be found in the Layers section under the Transition tab.
You can read the tooltips with descriptions of the settings by hovering over each one of them.

There are multiple sources available that you check that will help you get started using LayerSlider. The above mentioned tooltips, the demo sliders that you can import from the Template Store to see what settings we used and how we set them up exactly, and the documentation also contains useful information and examples that you can check and read on the following url: https://support.kreaturamedia.com/docs/layersliderwp/documentation.html

There are a lot of premade slide transitions that you can choose from in the Slide Transitions list. In case you do not find any that fit your needs you can edit them or create a new one with the Transition Builder. 
Please note that you do not 'choose images' in the Transition Builder as you are building the transition itself, not just an animated image. The transition that you create there can be applied on any slide background you add later in the Slide Background Image section.

Unfortunately we do not have video tutorials available at the moment but we are planning to create them in the future. In the meantime you can use the alnternative sources that I've mentioned in my previous reply: documentation, tooltips and demo sliders.