How to remove Search Bar in Product theme?

I found this thread... but still need some directions. https://premium.wpmudev.org/forums/topic/remove-search-bar-in-product
1) can the child.css be in the child folder or do I need to create all of the directories to mimic the original product theme?
2) what should the final code look like? i have...

/* custom / child css */
#search-bar {
display: none !important;
}

#signup-section {
display: none !important;
} 

/* 303069-1398288490 */