I think you're on the right track. It's literally been years (and years) since I've set Notes up to connect to one of my internet accounts, but that's what you'll want to do.
I no longer have the notes 6 help file, but it should be pretty much the same steps.
See if this helps:
https://www.ibm.com/support/knowledgecenter/SSKTWP_8.5.3/com.ibm.notes85.client.doc/locacc_acc_inet_mail_via_con_t.html