So you've created your header using Canva or PicMonkey, or some other creative tool, but what now?
It's time to add that gorgeousness to Blogger.
Open up Blogger, log in, and click on Layout.
You should see a section that says Header.
Click on the small 'edit' and a new window will open up, it will look something like this:
In the Image section make sure the 'from your computer' is selected and click on Choose File.
Find the header you created (and hopefully saved to your computer), click on it and click 'Open', or hit enter.
Your header should appear in the space, looking something like this:
Next you need to select 'Instead of title and description', in my opinion this is the best option.
You can add a description if you like, but with that option selected it won't show up. It is entirely your choice whether or not you want a description anyway.
Now you need to check that your header is showing up on your blog.
Click on 'View Blog' right at the top of the page.
Your blog should open up in a new tab or window. Check that everything looks good.