Thesis Introduction: First to be Drafted Last to be Finalized.
In terms of writing, Introductions are often the first to be drafted, and last to be finalised. we’re usually still re-adjusting the Introduction when everything else is finished. Really we can't get the Introduction finalised until we know how everything ended up. But this is why it is good to start with the Introduction. It makes us think about the whole thesis or article. We have to tell our readers about the whole thing in just a few sentences.
What do you need to say in an introduction? Imagine someone who is very busy looking at your Candidature Proposal. They want some quick answers.
They have no time for waffle. They want to know:
What is this about?
Why does it matter? Why does it need doing or need saying?
How does 'what you say' fit in with 'what we already know'?
(And maybe) How are you going to structure how you say it?
In short, the reader wants to know whether it is worth reading. So, you have to give them a quick idea of why they should.
Reference:
Adams, R. (2005). Demystifying the thesis. Victoria University.