Blow is a verb which in simple terms refer to a current of air or movement caused by it.
A cool breeze was blowing in the morning.

Now let us add different prepositions to this verb and see how it takes different meanings:

Blow out means to extinguish a flame by blowing.
He blew out all the candles in one breath.

Blow up means to inflate or fill with air;
Let us blow up all the balloons before the birthday girl arrives.

It also means to destroy or explode;
They blew up the building to cause anxiety and panic among people.

The phrase also means to lose one’s temper or to rebuke severely.
The boss will blow you up if you show him this useless presentation.