Generally you have 7 pins for the segments and an extra pin for the comma or punctuation.
This requires 12 pins, and some displays have more, they are simply unconnected and You do not connect them.
If you want us to give you advice on what is best, please give some links to some possibilites we can chose from. Generally 7-segment LED displays have very short pins and may not get a good contact in a solderless breadboard.
// Per.