The "media" folder would be the folder that contains the installation media. So wherever you are running "setup.exe" from is the folder you would use for that.
IF you don't have the installation media (ie you are using programs and features to change the configuration), you are going to need to download or find the installation media. If you have a visual studio subscription, you can download it from there. Otherwise you may need to ask one of the other DBA's (if there are any) or someone from your IT where they store the installation media for SQL Server 2019.
I would be hesitant to get the installation media from any source other than Microsoft OR someone I know and trust personally.
Also, after installing SSIS and SSRS you are going to likely need to install all of the SQL Server patches to get it all up to date, but those are easy to find on Microsoft's website.
This link (Microsoft) gives you access to download it, but it is the trial version. You will need your license key to use the full version and I am not 100% sure if this will let you add features to an existing install: