On the Samsung Galaxy S6 there is the possibility to couple the mobile LTE data connection with the Wi-Fi and thus obtain an increased download speed. This function is called "Download Booster" and can be used as follows.
Enable the Download Booster as follows:
Open from the home screen: Menu --> Settings -->More Connection settings
In this menu you can select "Download Booster" now. Drag the slider from "Off" to "On" to activate the download booster on the Samsung Galaxy S6.
Now, when you download a file with the Samsung Galaxy S6 from the Internet, which is bigger than 30 MB, then the Download Booster adds the LTE connection, which results in a faster download.
You know now how to turn on the Samsung Galaxy S6 download Booster.