If you are using one large mould, add sugar and water in it and heat it directly on stove. Once the edges starts to caramelize, start swirling mould to make the process even on all sides.
You should reach a dark brownish golden Color and let it rest aside while we make the milk mixture.
You can also make caramel in a pan and pour it into equal portions in 4-5 small moulds.

Pour milk in a sauce pan, add condensed milk, agar-agar, mix and switch on stove.
Bring milk to boil, stirring frequently to avoid skin to form on top.
Once milk has boiled gently pour it over the mold.
Chill in refrigerator until set.

When ready to serve, gently press the edges to loosen pudding from the mould then flip them over a flat serving plate.
Serve chilled!