Njeri, I am not certain what you are asking, but in response to your question about the 4P's of marketing, here are my thoughts. In my professional experience, and in teaching at the university level, there's really no "order" to follow. Generally, I like to see product, place, price, then promotion. You want to create a product that certain people are looking for, making it available when and where needed, at a price point that your customer is willing to pay, and then how you will make it know that your product exists.
Also: what are you manufacturing? I have many years of experience in that field, and perhaps I can assist.
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Njeri, To echo John's comments, there is no "true" order. Research as much as possible the item/s you are manufacturing. Drill down to understand who you are targeting (demographics), their buying behavior (psychographics), what's important to them, what makes your product different, what problem does it solve. Also investigate your competition, review, and price point.
As it relates to promotion, outline your digital strategy and ecosystem. Is your target market more likely to shop on Amazon, Instagram, FB or direct web or all of the above? Is your website & mobile presence fully optimized w/onsite & offsite SEO? Take the time to outline your entire plan with a methodically, strategic approach. Good luck!