An い-adjective goes straight before a noun to describe it, in the same form that ends a sentence: おおきい大きいいぬ犬, "a big dog". Nothing comes between the two.
な belongs to the other kind of adjective, and の joins two nouns. Neither goes after an い-adjective.A few な-adjectives end in い too, and they take な before a noun. きれい and きらい are the ones you meet first.
These go beyond one plain adjective before one noun.
The negative and past forms also go straight before a noun.
To put two adjectives before one noun, the first goes in the くて-form.