Running a blog on blogger.com aka blogspot is so easy but when you upgrade your blog by changing your CMS platform or setup a domain name with your blogspot blog.
You have upgrade your blog what will happen with your old blog? Want to delete it or get some traffic from it. If your old blog is alive and gives you a lot of backlinks then it help your new blog to getting rank faster in search engine.
If you decided to delete your old blog then you miss a lot of traffic from your blogger blog.
So what I do?
You should redirect your old blogger blog to your site or another url (where you want to send these traffic). But blogger custom redirect feature give you only 10 redirect and you don't redirect your home page.
So you have to paste some codes in your blog. And this is the code you can paste on your blogger's theme after <head> section.
<meta content='#;url=https://www.ujjwaladitya.blogspot.com' http-equiv='refresh'/>
This is an exam link whose all traffic is redirected to another blog. Check it.