Apps purchased from the official Google Play store can only officially be installed through having the phone itself connect to the internet. You can buy the app from the web site and tell it to queue an installation to a device, but officially the device itself must be connected to install or update apps.
Android does support unofficial app distribution as well though. If someone gives you a .apk of their app you can just copy it to the phone and select it from the file browser to install it. You can update apps installed from the Play Store in this way as well, just the first install needs to be done the official way to get the license loaded.
Music is just files, you can copy them on and off the device in basically the same way as an old MP3 player unless you bought from a DRM-based provider in which case they'll be "protected" somewhere else.
There's no real need for an iTunes-like setup with Android. Your PC has no need to be involved in the app installation process and everything else is just normal files you can manage with the file manager you already have.
Android does support unofficial app distribution as well though. If someone gives you a .apk of their app you can just copy it to the phone and select it from the file browser to install it. You can update apps installed from the Play Store in this way as well, just the first install needs to be done the official way to get the license loaded.
Music is just files, you can copy them on and off the device in basically the same way as an old MP3 player unless you bought from a DRM-based provider in which case they'll be "protected" somewhere else.
There's no real need for an iTunes-like setup with Android. Your PC has no need to be involved in the app installation process and everything else is just normal files you can manage with the file manager you already have.