Goverment gateway accounts / self assessment

[ApeShape]

I have to make my first self assessment submission, never done this before so I'm trying get the swing of it. Now, I have set up government gateway ID's (for my company) and I'm sure I have in the past too for checking stuff like how many NI credits I have. But any way, I've just realized you can register the same email address over and over again. I'm pretty sure that's what I've done which is utterly confusing. Which account do I use?

Or wait, do I do this through my companies government gateway?

Confused, I'm probably a simpleton.

[northernladuk]

Company govt gateway for personal self assessment?

[ApeShape]

Company govt gateway for personal self assessment?

I'm way off the mark as you can see, thanks.

Just googled national insurance credits, took the first link (gov.uk obviously) went through the extensive verification and finally got in. So it's an email-free login to access your personal stuff? Even more confused about what purposes of the email-login based accounts are for.