Starting a meeting:

Hello, thanks for agreeing to see me.
Hello, it’s good of you to come and see me.
It’s good to see you again.
Shall we get down to business?
There are a few questions I’d like to ask: …

Ending a meeting:

Well, I think that covers everything.
I think that’s about all for the time being.
So do we agree that…?

I’ll put these proposals in writing and fax them to you tomorrow.

Here are some more expressions that you can use in the meeting:

What does everyone think about this?
Let’s put this to the vote.

I suggest that…
I propose that…

I agree with that suggestion because…

I don’t quite agree with that point because…

I think it’s time to adjourn the meeting.
I think we’re running out of time.

Is there anything else we should discuss?
Is there any other business?

These expressions which are used when explaining procedure:

To explain the order in which certain things are done:

First of all…
The next thing you have to do is…
…And them finally…

To add a further point:

Make sure you…
Oh, and by the way, don’t forget to…
Oh, and be careful not to…

To check that the other person is following you, or has understood:

OK, so is that clear?
Does that seem to make sense?
So there we are. Do you have any questions?

If you want to ask someone to explain something to you, you can say:

Excuse me, could you show me how to…?
I wonder if you could tell me how this works?

If you haven’t understood the explain, or if you can’t follow the instructions, or if you want to check that you’ve understood so far, you can say:

I’m sorry, I didn’t quite follow you there.
I’m sorry, what did you say that part was called?

When you think you’re understood, you can say:

If I’ve understood right…
So is the basic idea that…?
You mean…