PETSc is available from multiple package managers. Depending on your exact needs (for example limited use of external packages) they are possibly the easiest way for you to install PETSc. Always verify that the package manager is providing a recent enough release of PETSc with support for the external packages you need. Some package managers provide separate packages for the complex number installation of PETSc.

Information and tutorials on setting up a PETSc installation.