Although Delimiting is not part of the original Design Thinking Cycle, it goes without saying that you need to limit the scope of your research. You do that by defining the customers you want to serve and the nature of your business. This can be done in a very brought sense. Customer groups can be defined by country, gender, income, social status, motivation etc. The nature of your business can be defined by type: service, manufacturing, intermediary, trading, licencing, etc or by industry: food, energy, education, health, finance etc. Base your choices primarily on your personal interests, your strength, your skills, your assets, your ambitions and your passion.
Besides defining customer groups and nature of business, its essential that you state your level of ambition. Quantify the size of your business and the impact it has socially, environmentally en financially in five to ten years.