Clarifying key terms

Question 1

introduce a general topic

Answer 1

I want to begin by talking about …
What I’d like to do is outline (exposer)…

Question 2

introduce a sub-topic

Answer 2

Here, I’ll focus on…
What happens here is that…

Question 3

introduce a clarification or an explanation

Answer 3

I’m going to highlight…
This is when…
In other words…
What’s meant by this is that…
That’s to say…
In this case…