The shorthand way for organic molecules is called a bondline structure.

There are a number of rules for bondline structures but for the question in hand we only need to learn the 3 below:

1. "Corners" are carbons
2. Lines are bonds
3. Carbon needs 4 bonds to be neutral. When less than 4 bonds are visible in the structure, and carbon still doesn't have a formal charge (+ or -) then this means that there are hydrogens not shown that completes those 4 bonds.