Since both the long form possessive adjective (mío) and a descriptive adjective (linda) goes directly after the noun, as in
Mi amiga linda está aquí.
and
La amiga mía está aquí.
i am confused as to where to place the possessive and descriptive adjectives when they belong to the same sentence.
La amiga linda mía está aquí.
or
La amiga mía linda está aquí.
Forgive me if I use a slightly different example, which makes it easier for me to imagine using in realistic conversations. This will show the same issue that you were illustrating.
Vamos a usar el libro mío, que está en la cocina.
Vamos a usar el libro clásico.
How to combine? You're right to wonder how to accommodate two adjectives after the noun. Answer: recast. I can think of a few possible ways:
Vamos a usar el libro clásico, el mío, que está en la cocina.
Vamos a usar el libro mío, el clásico. Está en la cocina.
Vamos a usar mi libro clásico, que está en la cocina.
Vamos a usar el libro mío, que está en la cocina. Es el clásico.
[Note, Spanish has two verbs that both translate to "is": one that essentially provides a definition, "El libro es azul," and one that describes a dynamic, changeable quality, "El libro está mojado" | The book is wet. That's why I edited your question and changed "es" to "está." You will get to this pretty soon, I think, in your studies.]
