Hi there, nice to see you.
Yes, you need java to run this game. Java is a software that will allow you to open that file you downloaded from here.
So, there are 2 types of Java, Java 32 bit and java 64bit, according with your Operating System on your PC. You need to discover if your OS is 32 or 64bit.
Sometimes running the game with java 32bit on a PC that use a 64bit OS can cause some issues.
If your PC is not too old, Java 64 bit is usually recommended.
So:
1) Check wich version of windows you have (operating system OS): go in control panel, then system, then check for operating system.
2) go in control panel, then programs and features (hope it's the right name in English), and unistall(delete) the previous version of Java you installed
3) go here:
https://www.java.com/en/download/manual.jsp , click and download:
Windows Online if your OS is 32 bit
Windows Offline (64bit), if your OS is 64bit
4) Install this program following the instructions
5) once complete, if still you are not able to open the file (should not be the case) you can right click the game file and choose "open with" now you need to locate the Java software you have just installed and tell him to open that file with Java....this is a bit hard, maybe ask your grandson for help

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This is a very beautiful game, very in depth and nice, but could be a bit hard to start.
So here a beginners guide, even if outadated in some regards is very helpfull:
viewtopic.php?f=42&t=40714And here the Wiki of the game (it's like a dictionary of the game, you can search almost everything about the game, items, tools, and so on):
http://ringofbrodgar.com/wiki/Haven_and_Hearth_WikiHope to have helped, sorry my English, but I'm Italian .... enjoy the game and have fun
