Symetrize does not apply. I followed all the steps
Hey YYAbrahaim,
A few things to check,
1, The bones have the correct name. You must use .L (or .R) at the end of the bone name to be symmetrized.
2, The ear bone is parented to the head bone. The head bone should be the daddy.
3, The head bone is on the same line of symmetry as the Suzanne GEO