The bitrate that you choose determines the quality of your video and the file size. The standard units for bitrate is bits per second, or bps. Sometimes bitrates are expressed in Kbps (kilobits per second) or Mbps (megabits per second). Do not confuse Mbps and Kbps with MBps and KBps. A lowercase 'b' refers to bits, an uppercase 'B' refers to bytes.
From your question it seems you are more concerned about size than quality, so I recommend that you pick what is a reasonable file size and deduce the bitrate that achieves that size.
For example, let's say you want your file to be 200MB. First convert this size to bits:
200 x 1024 x 1024 x 8 = 1,677,721,600 bits
You also said that your video is 11 minutes, which is 660 seconds. So now we obtain the bits per second:
1,677,721,600 bits / 660 seconds = 2,542,002 bits per second (approximately)
From the above, you know that if you pick a bitrate of 2,500,000 bps (same as 2,500 Kbps or 2.5 Mbps) then your file will end up being about 200MB in size.
So now what's left is to pick a resolution and frame rate. Once you know your bitrate, you have set an allocation of bits for each second of your movie. To get the better quality you should now pick the smallest resolution and slowest frame rate that works for your needs, as that will assign the maximum number of bits to each frame, giving you the best possible quality.
If I create a video from 10 pieces that have a bitrate of X, can I create a video which has a larger bitrate?
You can use any bitrate you like, but if your source clips were encoded at some bitrate X in the camera, going to a higher bitrate will just waste space without increasing the quality, since you can't add detail that was not in the original recording.