Access old Legacy Blogger automatically
1. First, in your desktop, right-click your wallpaper. Press New > Shortcut.
2. In the Create Shortcut, paste the link below in the location. And press the Next button. Make sure to change the 19 zeroes with your own blogger blog ID. You can see that ID in your blog's URL inside Blogger also.
3. In the next step, just type a name for your shortcut, like Blogger, Blogger.com, Blogspot, whatever you want. Click the Finish button.
4. Your shortcut is now in your desktop. You can try opening it, and it will automatically direct you to your Blog with the designated ID editor page.
You can also customize or change the icon of your shortcut to a real Blogger icon like the image seen below.
You can follow the tutorial here of Changing the icon of a shortcut file.
Update: To be able to make the shortcut link functional, you need to click first the "Revert to Legacy blogger" link if you are already using the current new Blogger platform. If not, the link you created will only redirect you to the latest Blogger and not the old one.