Question related to IBM Host On Demand

I am new to IBM HOD and I am running IBM Host On demand version 12.0.1 on my window machine.
I came to a pop up message saying that “Your Client Platform is not capable of running Host On Demand. No java Support was found on your browser. Contact your admin to obtain a necessary Java 2 support.”
I wonder of how could I solve this issue given the fact that I already installed Java JRE 1.8.0_241 on my PC. Furthermore, I go to the IBM central and I see the Java SDK Version is recommended for the IBM HOD version 12.0.1.
I would like to ask if I need to download the SDK and why ? The reason I am asking Why because of I already had the Java JRE 1.8 on my window machine so why I need to download the SDK since I am reading on Google that SDK is for the WebSphere server and I am running IBM HOD on my window machine?

Many Thanks for all of the helps.