I volunteered at a summer day camp for multicultural children that spoke little to no English.
"multicultural children" sounds awkward to me. How about just "children who does not know English or cannot speak it well"?
I believed that media such as songs, games, and movies would be helpful
It wasn't easy.
What wasn't easy? Preparing the class? finding materials? Always be careful of using "it" cuz you have to explain what it refer to. ^
I spent hours that weekend looking for suitable materials: past and current teachers were contacted, libraries were explored, and of course, the famous Google brought up thousands of pages that had to be individually sorted.
I just thought it is not that necessary to use a passive structure in this very long sentence. You can just say "I contacted many past and current teachers, explore... Blah blah blah". but this is just my idea. you dont have to change if you prefer your original.^
It wasThe uncharted territories and thoughts of failure floated through my head. However, all of my worries melted away as i saw the children were immersed in the language and smiling at the same time.
Again, this is just my own idea. You can always choose to use the words that you like better.