[sql-server-express] SQL Server® 2016, 2017 and 2019 Express full download

When you can't apply Juki's answer then after selecting the desired version of media you can use Fiddler to determine where the files are located.

SQL Server 2019 Express Edition (English):

SQL Server 2017 Express Edition (English):

SQL Server 2016 with SP2 Express Edition (English):

SQL Server 2016 with SP1 Express Edition (English):

And here is how to use Fiddler.