An EndNote library is saved when you create it - make sure you choose the location where you want to save it to or the default will apply.
To change the layout of your EN library use the dropdown options in Layout at the bottom RHS of your library - the default display for the Reference Panel is - Right but you may want to change it to Bottom - Split.
Once you have installed EndNote it will be in your startup menu and can be opened from there - click on EndNote icon
The box below will only appear the first time you start EN on a computer - you can select to Create a library or Open an existing one
Name your library and choose the location/drive to save it to - the default options can be changed. My EndNote Library.enl is the default file name.