Hi and welcome to Ask Ubuntu!
You can follow the following steps to get a successful Ubuntu installation using Wubi
1.Setting the installer up
^^That is how your Wubi Installer would look. Set up a username, install location, password, language, size and you're ready for the next step.
This is fairly easy, and the user (i.e. you), have no role to play in this. Wubi downloads all that is necessary whilst allowing you to carry out your required tasks on Windows.
3.Completing the setup
Now that you have completed the setup, you need to reboot, do note, rebooting is necessary to complete the installation.
This is how your screen should look post rebooting. Choose Ubuntu and you can boot into your fresh installation. Hope this helped!
Note: These images do not belong to me I have taken them from this link