Congratulations... I'm in the middle of starting from scratch on my PC. God help us all if that doesn't work.
As for your oversized desktop, go to control panel, then display, and set the zoom to 125%. With the browser choosing, it's just about choosing the default... you can have both installed. Next, for brightness, go into control panel and in the power settings
you will find the adjustments for dimming the screen (power options -> choose plan settings).
Lastly, with the start apps, you can use more than one by dragging from the top and moving it to a side. You said "browser apps"... if you're talking about chrome or IE, you can make it go to desktop mode by clicking in the settings on the right (for
Chrome) and telling it to open in desktop mode. For IE, I think there's a similar control.
If the brightness doesn't work, open the charm bar (windows+c) and click on the monitor and set the brightness from there.