All ways are already easy. Firstly, backup everything including files and database. Then just upload the new files to the web server except config file. Then install as if you are doing a new install. This process will also upgrade your database. And lastly, make the template arrangements and you are done.
Might want to wait a few days, 3.2 is just being released, if you are going to upgrade might as well upgrade to the latest version
1) Backup EVERYTHING 2) Upload all files except config overwriting your previous installation. Make write permission to config 777 3) re-run the installer (this updates the database without losing data) 4) change write permissions for config back to 444 5) make any template or other chages you had previously