Back in the middle of the 20th century, the path to a concert career was simple. First you were selected to study with a famous teacher, then anointed by one of only a small handful of concert management 'impresarios', then you toured the world. If you were not one of these lucky (and talented) few, you were out of business.
Today, its different (and better!). Attaining great concert management (someone charged with getting you concert bookings and overseeing your career) is still a goal for many, but its not the only option. In fact, the best way to get management that works well for you is to learn as much about the business as possible. You also need to prove to a management company that you already HAVE a viable career that they can make money from. (This is a good thing for you - since they get paid a percentage of your concert earnings, the more they make, the more you make.)
The simple act of doing the work to get your first gig was the beginning of becoming your own management. Now join (if you are in the U.S.) Chamber Music America, and learn from their resources. Go to the Musical America website and view the 'Find Contacts' section for listings of concert presenters. Attend a regional and/or national booking conference of Arts Presenters to see how the professionals represent artists. Note what materials they use: printed brochures, video & audio, the tables and backdrops that make up each booth, etc.. Try to create the materials you will need to represent your ensemble, then reserve a booth and actually 'do' a conference. You will probably NOT get any bookings (most concert presenters will hire ensembles only after they have passed on them in several previous years). The experience and networking you will gain, however, will be invaluable. You will also get to meet and observe managements in action over a period of several days. Remember that you are in this for the long haul.