Verifying Shopify store in Merchant Center

[Organiqa-D]

Hi Community,

Could anyone help me and walk me through the steps

to verify my store's website in Merchant Center?

Whenever it comes to coding, always something strange happens and shows on my website or the theme wouldn't update and I have to redo my design again. 
Unfortunately I don't know WHERE EXACTLY to place the code.

Thank you in advance!

Kind regards, 

Barbara