Integrate the Email Collection Bar to Brooklyn Theme with placeholder option 

Step 1: Select the last option under the "position" setting in the bar configuration in the App, and save the change
Step 2: Go to Admin > Online Store > Themes
Step 3: Click the "..." button on the right hand side, and select "Edit HTML/CSS"
Step 4: Please check there is file named "header.liquid" under the section folder
If yes, find line <header class="site-header" role="banner"> in header.liquid file, and then place <div id="ecb_placeholder"></div> above it in a new line
If not, find find line <header class="site-header" role="banner"> in the theme.liquid file, then copy and paste <div id="ecb_placeholder"></div> above it in a new line

Step 5: Click "Save"

NOTE: Do NOT forget to select the last option under the "position" settings in the bar configuration in the App, and save the change