Hi Chris. First you need to have a business plan and include there a marketing plan. The following link will provide you orientation on how to create that plan: https://managementhelp.org/businessplanning/index.htm , which indicates also the steps to develop your marketing plan, under "Section - Marketing and Sales Plans". The length and details of both plans - business and marketing - will depende of the nature of your company, age, service / product, etc. For your future inquiries in this website I would suggest you to provide more information. Have a great time in this phase of your business!