While the earlier sections of your business plan explained your goals, your operations plan describes how you will meet them. Your operations plan should have two distinct sections as follows.
Everyday short-term processes include all of the tasks involved in running your t-shirt business such as serving customers, procuring supplies, manufacturing shirts, etc.
Long-term goals are the milestones you hope to achieve. These could include the dates when you expect to serve your 1,000th customer, or when you hope to reach $X in sales. It could also be when you expect to hire your Xth employee or launch a new location.