If there is a chair near my I would say:

tēnei turu
this chiar near me

If a chair was near you I would say:

tēnā turu
that chair near you

And if a chair was away from both of us, I would say:

tērā turu
that chair over there

So, I could say:

He turu tēnei.
This is a chair (near me).

He turu tēnā.
That is a chair (near you).

He turu tērā.
That is a chair (over there).