1.) Find out where you currently have HO installed
Right klick + "Properties" on the shortcut in your startmenu (or desktop)

2.) Download the new HO release
e.g. from the official site or one of the latest Beta versions
If your HO is currently running, exit it now!

3.) Right klick -> Extract all...

4.) Choose/enter target folder from step 1.), Next...

5.) Overwrite existing files...
... "Yes, all". Only the program gets updated, your HO data remain untouched.

6.) Wait until everything gets extracted, done.
Start HO as usual.