i have generated with verified code frm bitaddress.org.
Verified code? You mean you verified the signature of the source code? As far as I know, having the source code of bitaddress.org is enough to generate keys. You just open the html file in a browser.
If you did, then you're fine. Bitaddress.org uses a secure source to get the entropy, using Crypto.getrandomvalues(). Same Iancoleman does.
step1: go to always offline airgaped pc recent clean install windows and install electrum
Just a recommendation: Burn a Linux OS in a CD and then boot from it. Once you're done with this procedure, remove the CD.
step3: notedown the address for stacking sats
You should actually note down the master public key instead of just one address.