Unfortunately I do not see any other posts from you so it is hard to know what the issue is exactly.
But the procedure for installing Start8 on Windows 8 or 8.1 is the same. It is very simple indeed.
1) Download the Start8 installer
2) Run it
3) Follow the on screen prompts
4) Once installed the Buy / Try / Unlock prompt should appear.
5) Pick unlock (if purchased), enter your account details on the screen and click next.
The product should then be unlocked and the start button will be on your taskbar.
Be aware that on Windows 8.1 you will need Start8 1.2 or later. Earlier versions would not show the start button as the Microsoft one blocked it.
If you have had a particular issue then please do contact support@stardock.com so they can assist. That's what they are there for.