Hi. The problem you have is you aren't selecting a 'community.' At the bottom of the page, there should be a box that says this:
You have to click on the "Browse communities" button and select the community that best suits your topic. For example, if your topic were to be about "Apple music on a Mac," you would just type that into the search column, and click on the blue text that says 'Apple music on Mac" (see image).
If nothing shows up, try searching just 'apple music' or just 'Mac.'
After you click on the topic that best suits your topic, the popup window should close, and will by some text will replace it, that looks something like this:

You can actually click on the part that says 'Apple music' to see other questions related to your topic. If you make a mistake, all you have to do is click 'change.'
If it still doesn't work, make sure you fill out the 'product' and operating system.
The product is simply the device you are using (iMac, iPod, iPad, iRaq 😝), and the operating system is simply the version you are on. On a Mac, you can check it by clicking on the apple in the top left corner, holding down option, clicking system information, and reading the text there. For example, my Mac is in Version 10.11.6 
On an IPad\IPhone, go to Settings > General > About, and the version will be under 'version'. My version is a 10.01.
I hope these strategies work!
-MGengarOK