Please explain Ricoeur's concept of self as narrative. And how it is based on Aristotles's mimesis?

Narrative is an important concept in the work of Ricoeur. It is related primarily to the identity of the self and ethics, which treats of the relations between the self and Other. Indeed, for Ricoeur, selfhood cannot truly be separated from the Other. The very existence of the self implies the existence of the Other. Thus, for Ricoeur, the problem of intersubjectivity, the relation between different human subjects, does not arise.
The best way of approaching Ricoeur's concept of the self is to see it as occupying a middle position between two competing theories. On the one hand we have the isolated, disembodied self, or cogito of Descartes. On the other, the radically de-centered subject, determined either by language, in the case of Derrida, or discourse, as in the work of Foucault. According to Ricoeur, the self is neither fully as fully stable or as self-transparent as in the Cartesian picture, nor as incoherent or as self-alienated as the deconstructionists would have it.
It is in Ricoeur's middle way between these two radically different pictures of the human self that the concept of narrative comes into play. The human subject's relation to itself is one of active interpretation. And this self-interpretation emerges through narrative. Narrative, as Ricoeur understands it, isn't simply about telling stories; it's a way for the self to interpret and understand its past, present and future. For instance, when making sense of the past, we draw together different memories and events to make them into a coherent whole. On one level, we're telling stories about ourselves. But on a much deeper level we're making sense of who and what we are. This is what Ricoeur refers to as "emplotment," as if we were establishing the plot of a story, for example.
The use of narrative in this way helps us to gain a much broader perspective on our lives. By seeing ourselves as part of a story, we not only come to a deeper understanding of our past, but also of the many possibilities of our future. Seeing the future as narrative allows the self to project itself forward into a world of possibilities and potentialities for action. We can see here once again how Ricoeur's concept of the self radically differs from those of the Cartesian and deconstructionist approaches. The self is its own author, albeit inextricably linked to the fate of the Other. In Ricoeur, the self enjoys a large measure of freedom in a way denied to it by the essentialism of Descartes and the radical decenteredness of Derrida.
Ricoeur is strongly influenced in his concept of the self by Aristotle's theory of mimesis. When related to a work of art, mimesis refers to a representation of reality. However, this raises the question as to what constitutes reality. For Plato, ultimate reality consisted in the Ideas, supra-sensible entities of which earthly objects were mere copies. For Ricoeur, Plato's understanding of mimesis is a problem, as it leaves no room for human interpretation, which as we've seen is at the heart of his concept of the self. Mimesis, as Plato has it, leaves human beings out of the interpretation of reality.
So Ricoeur turns instead to Aristotle and his theory of mimesis. Aristotle sees mimesis as an active and creative interpretation, one that doesn't simply reflect reality as in Plato. In other words, human action is an essential part of mimesis. Ricoeur is indebted to Aristotle for his use of emplotment. Mimesis happens by the arranging of events into a coherent narrative whole, or plot. In this sense, the narrative of a work of fiction augments the meaning of the world of human action by creating a world of its own, one with its own internal structure and coherence. It also mirrors a strictly human reality as opposed to Plato's idealist construct.
What Ricoeur is attempting here is the universalization of the insights that Aristotle made in the Poetics. He takes Aristotle's use of mimesis in relation to drama and applies it to narrative in general, not simply fictional narrative, but the historical narrative in which the self's understanding of past, present and future is situated.
https://plato.stanford.edu/entries/ricoeur/