Welcome to our world of "specialization...." Like anything, we recommend that you begin by collecting information. The best way to do this is to contact several area landscapers and make them aware of your plans. ALERT....the numbers you bet may be shocking, so don't go with only one estimate...be sure to get several.
This process will help you to become informed about the process and help you to clarify your options.
TIP....once you have an appreciation for what needs to be done and how to accomplish it....many people elect to manage their own project and save thousands by being your own project co-ordinator. If you have the time and interest, this avenue can be challenging and fun.
Good luck collecting information and becoming informed.