i create a wallet > private key > key in 30 digit private key > sweep
Are you creating a new wallet with your private key?
If you're certain enough your computer is clean, and if you've made a backup of your Electrum seed words, this will just work.
one thing I'm not sure is the "address" that ready filled up underneath where i key in my private
key, is it my electrum wallet address?
I think so. But it doesn't hurt to
check!
second, should i choose ETA as a fees?
That will work. Fees are quite low now anyway.
once i sweep it, it will show up in my electrum wallet?
If all went well: yes.
i just want to be 100% certain I'm doing it right and the ready filled address is my electrum wallet address.
For 100% certainty, I'd go with the much slower but more secure offline setup.
After you're done, you may want to read up on
Forkcoins (ignore the dollar values in that post, it's outdated) and sell some of them for some extra Bitcoin.