Clean: you don't need soap and water every time. Usually you can get by with a good soapless scrubbing and a thorough rinse.
Look for a piece of chain mail - they're all over Amazon - because that's what I use and it has proven VERY effective, and on more than just cast iron. Use that to get the crud off. Follow up with a good rinse, dry it thoroughly and you're done.
Seasoning comes two ways: oil and bake, or just through use.
Oil and bake: heat up a clean pan to about 300, smear with a thin layer of grapeseed oil and put in the oven at 400, upside down, to bake for an hour. Wipe off the excess oil. Allow to cool, repeat two or three more times.
Use: oil it, cook, wipe it clean. Repeat for decades.
Seriously, it isn't rocket science and people say there's a right way and a wrong way, but the only wrong way is when you wash your CI with soap. Don't do that. Avoid that, never put it away wet and you'll be fine forever. I have a Griswold small logo pan from my grandmother, that she got from HER grandmother. Be even a little conscientious with your pans and they'll become heirlooms.