You can as gustavwiz notes, type in your address bar, opera://settings to get the settings menu.
You can alternatively press Alt P to open the Settings section of Opera. (Another way is to click on the Opera logo in the upper left of your browser to open the Opera menu and then click on Settings). Note under Settings the "On startup" section under the browser tab. There you can put a check in Open a page or specific set of pages. And then set the page or pages that you want for your home page.. That's how you can pick your own home page when you open the browser, if you prefer that to using the speed dial for your home page.
By the way, you can also make each new tab your home page, instead of the Speed Dial. Then you need the extension Home Page in New Tab, which you can download from this link. https://addons.opera.com/en/extensions/details/homepage-in-new-tab/?display=en
The speed dial though is pretty nice, so you might want to play around with it. You can not only create a lot of your favorite links, for each position of the speed dial, but if you want, you can drag one link on top of another, and create a folder of links for each position on the speed dial. You can also beautiful beautiful wallpaper for the background to the speed dial. One way to do that is by right clicking on an empty space on the speed dial page, and then clicking on change theme.
I think you will enjoy Opera as you get used to it a bit. Best of luck.