How do I build an APK downloading site?

Sites like
apkpure
http://www.appsapk.com/

etc.

I have a way in mind to build it better than these guys. But I don't know how they manage to get all the apps. Over million apps, getting their apks manually is not worth the time. So obviously these guys are all using something. Apparently, no one seems to know how they do it.

Please put me in some progressive direction. Thank you BHW.

Do it manually and stop wasting time. Hire a few VA's to help. It's a hustle if you want to do it properly.

These sites basically scrap data from play store and store it on their server.

thank you