Can’t find log-in screen for guest

I’m embarrassed, but what the hey – nobody knows everything…

I’ve been merrily posting along for over a year, and I’ve just signed up 2 contributor/guest bloggers. I went to admin and set them up as authors, I emailed them the password and sign in but I have no idea what the url address is for signing in. I know it’s dumb.

My computer defaults and I never have to sign in.

Everything we’ve tried has resulted in a 404

My website is https://thingsyoushoulddo.com

thank you