Explenation how the ranking works
Down below you will find a image with the official ranks for Competitive CS:GO. There are 18 ranks in CS:GO. First you play 10 games and until the last match you remain unranked. AFter that your Rank is calculated and you land in your skill group. By winning games you can reach a higher rank, but be careful, you can also drop down.
CS GO Competitive Ranks Official