Homework for beginners JS

Hy!
Thanks for the answer
I have to introduce a word “strawberries” in a string “Ana has apples and pears” at a certain position, more precisely at position 6.

In the last message I started writing the code but I blocked my self after I write the function
I have already started to learn freecodecamp, only that I have reached only 40% and I have not yet gathered the knowledge necessary to solve this banality.