Zennia - the insert and delete buttons are normally on your keyboard.
1234 - The little tiles icon in the lower left is the Win8 version of the start menu. Click on it and it'll bring up the Start tiles. There you can find the tile that is called "desktop" and if you click on that you'll think you're back in Win7. If you upgraded from Win7 you'll see all your applications there on the desktop and you can pin apps to the bottom task bar just like Win7. If you want to change settings, which was also on the start menu in win7, or log in or out, slide your cursor to the right side of the screen and a popout will appear with icons for doing those functions.
ActiveX - If you're running the new IE 10 browser, which is what comes with Win8, run it from the Desktop (click on desktop in the tile menu). If you want to run unsigned ActiveX controls, which btw is not very secure but required for some games, do this: In IE, bring up the tools menu (looks like a little gear at right side of screen) and select Internet options. On that popup, click on Internet zone, then click on the Security tab, and on that tab click on the Custom Level button. The Security Settings - Internet zone box should appear. If you scroll down in that aways you'll find all the settings to change for allowing unsigned ActiveX controls.
Not sure what you're using for your email client, so I can't answer the other question. I use Thunderbird and all my stuff transferred over with no problem, but I was upgrading from Win7. This might be a question you have to google.