This is the 12581st most frequent Spanish word.
montarse
"Montarse" means "to get on" or "to ride."
In this case, 'montarse' indicates physically climbing onto or getting on top of an object, like a table.
El gato se montó en la mesa buscando comida.
The cat climbed onto the table looking for food.
In this sentence, 'montarse' is used to mean 'to get on' or 'to ride', specifically getting onto a bicycle.
El niño aprendió a montarse en bicicleta.
The child learned to ride a bicycle.
Here, 'montarse' is figuratively used to express joining or getting involved in something, like a project.