Different Interface



Getting this thing up and running has me a little confused.

My interface looks very different from all of the pictures I see posted on here. I thought maybe it was because I needed to update the software, but I'm having trouble with that.


After overwriting the old files with the new update files, when I try to go to the url for the update wizard: http://www.yourdomain.com/backend/index.php/update

I simply get redirected to my dashboard.

Thanks in advance,
From your screenshot the interface looks the current one to me.
However, starting with version you can actually switch the interface skins from backend -> settings -> customization.

Here's a video showing how to update mailwizz:

That's because mailwizz being a pretty huge app is split in different areas, like Backend / Frontend / Customer / Api where various things happen.
The screenshots you mention above ( https://forum.mailwizz.com/threads/how-do-i-import-subscribers.7/ ) are from Customer area, where you login as a regular customer of the application to send campaigns and handle your subscribers, while the screenshot from your original post is from Backend, which is basically the Administration area of the application where you handle customers and much more.
You can distinguish these by looking in the url (/backend or /customer).
P.S: From /backend area you can go to Customers menu item from left side nav, list all the customers you have (by default is only one, you) and impersonate them. Once impersonated, you'll get automatically logged into /customer area of the application.
Hope it makes sense.