Note Basics
Using these acronyms FACE and Every Good Boy Does Fine, you can learn the basic notes.
Ledger Lines
Ledger Lines are short horizontal lines that are above and below the staff (basic range of notes you learned earlier) to extend the range of notes. Each new ledger line represents a note that is one "whole step" higher/lower than the nearest note on the staff.
What is a "whole step"?
The distance between two notes on a musical scale. For example, moving from C to D or from E to F# involves a whole step because there are two half steps (notes) in between.
(if understanding how to read the ledger lines is hard, don't worry, it will come to you naturally at some point, for now just memorize the notes above if you must but try to understand the concept of ledger lines)