Imagine you and your family just moved to a new country. What are some ways you can assimilate into a new culture?

Notice how the people in your new surrounding act with other people, try to imitate how they react, respond, and interact.

Also notice their clothing. Different cultures wear different clothing as well, you wouldn't want to stick out in a crowd or you might bring unwanted attention to yourself (unless you want that)

then notice the way the talk or what language they speak.

if they speak a different language from what you don't know, then you should learn the language to best of your abilities to improve your social skills as well. this could also lead you to fit in more with the new culture