Hi, welcome. There are no secrets to a clean eating diet plan. Eating clean means avoiding processed foods. Read labels, even when you think you're buying something healthy. For example, I buy a lot of kidney and black beans in a can to toss in my salads. However I found out that most brands have a whole load of sodium in them. So I switched to Eden Organics which have 0 sodium.
Eating clean means eating mostly whole foods. Make things from scratch. When you shop at the supermarket shop from the perimeter, that's where the produce and refrigerated sections are, aka perishable foods. Shop very little from the aisles where the pre packaged foods are.
"If you pay attention to when you are hungry, what your body wants, what you are eating, when you've had enough, you end the obsession because obsession and awareness cannot coexist." - Geneen Roth