There are molecules that we can not see with our naked eyes. Protein is one of them.
You may see some proteins using PyMOL on your computer.
You could install free PyMOL in your terminal using brew:
Brew install pymol

Now, to see any protein there, use fetch command:
fetch 9DYH
You could get PDBIDs and more information from here: RCSB.
This is another useful command to arrange all PDBs in order: alignto
alignto PDBID (eg 9DW7), object=all_to_PDBID (eg 9DW7)

You could start learning about protein structure by digging more websites. 🤞