When making customizations to your Exchange template files, you do not want to directly edit the files as your changes will be overwritten when you update Exchange.
Instead, you'll copy the file you're wanting to customize and then make your changes. Then, in your theme, you'll create a new directory where you'll upload your customized file.
The directory that you create will depend on the file that you are editing. In each of the template files, you will find the directory path you need to create.
So, if you are editing the base-price.php file, the full path would look something this: wp-content/themes/YourTheme/exchange/content-product/elements/