You should now have the VNC installer program saved on your computer. On principle, you should run it through your virus scanner (often you can do this by right-clicking the file).
Assuming you get no warnings, double-click the program to start the installation. You'll see this dialogue appear:
Click the Next> button in the dialogue. In the following screen, you should select the option "I accept the Agreement" and click the Next> button to continue.
