The construction poner(se) a + infinitivo, prevalent in spoken Spanish, is used to mean to begin/start doing [something], to get something/someone to do [something], to set about doing [something] or to get on with [something].
This verb can be used as either a reflexive verb or a transitive verb.
1. Ponerse a + infinitivo
Read and listen to these examples:
In the examples above, ponerse a + infinitivo suggests the beginning of an activity at a specific moment, usually as an unexpected action.
It is also commonly used to talk about the weather in an impersonal way, as an unexpected action:
De repente se puso a llover.
It suddenly started to rain.
¡Se ha puesto a nevar!
It has started to snow!
2. Poner + (algo/alguien) + a + infinitivo
In the examples above, poner + (algo/a alguien) + a + infinitivo suggests that the subject of the sentence begins to do something. This time it is not reflexive but rather has a direct object.
Notice how in the last example above, the object refers to people (los niños), in which case the conjugated verb (poner) is followed by "a".
Here is a list with colloquial expressions using the verb poner/ponerse.
Learn more about these related Spanish grammar topics
Examples and resources
Q&A Forum 1 question, 1 answer
Se va a poner / va a ponerse
Yes, you can also say "va a ponerse a limpiar"; equally correct.