I'm an idiot:: set options now can't login to my site!

First of all, I am really a newbie, so I need “Help for Dummies” here! I had seen a number of logins and last URL visited that convinced me that I needed this plugin. I activated it, set the options that made sense to me, and seemed to be fine. I exited and then entered my WP dashboard via my browser shortcut, no problem. Then 5 minutes later while doing something in the dashboard I could no longer connect. I closed the tab, and then hit the shortcut and I get my homepage with a 404 error rather than the dashboard. I tried to change the login shortcut by entering the new slug I entered into the https://xxxxxxxxxx/wp-admin/index.php link but that doesn’t work. I don’t remember now – one option I entered a slug, another option the program chose a random something for something (told you I was a dummy!)

Trying the slug that I entered, hoping it is that simple (but not sure why the shortcut worked and now doesn’t!) – where do I enter that? I think I tried it in every way so that probably isn’t it. I desperately need to get into my site (podcast, and we’ve announced a new episode and I can’t upload it and don’t want people to give up on us!) Help!!! (For Dummies! ?? )

https://www.ads-software.com/plugins/all-in-one-wp-security-and-firewall/