Tertiary structure of a protein describes
Secondary structure denotes the configurational relationship between residues which are about 3–4 amino acids apart; or secondary level defines the organization at immediate vicinity of amino acids.
The tertiary structure denotes three dimensional structure of the whole protein.

Reference: Vasudevan 7th  ed, pg 38
The order of amino acids
Location of disulphide bonds
Loop regions of proteins
The ways of protein folding