This is the 111th most frequent French word.
mettre
To put, place, or set.
In this sentence, "mettre" is used to mean "to put on," referring to clothing.
Je vais mettre un pull car il fait froid.
I am going to put on a sweater because it is cold.
Here, "mettre" is used to mean "to place" or "to put," referring to placing items in a specific location.
Il faut mettre les livres sur l'étagère.
You need to put the books on the shelf.
In this context, "mettre" is part of the phrase "mettre en pratique," meaning "to apply" or "to implement," especially regarding ideas or advice.