Although setting up the My Sites web sites is described in this TechNet article, there are a couple of things you will need to take care of to get the complete My Sites functionality working, especially if you don’t want to use the default settings.
First of, where do you find the place to enter the settings?
On the start page of the Central Administration you will find a link to "Manage service applications" under the "Application Management" header. In the list of service applications, choose "User Profile Service Application".
This will bring you to a page where there is a paragraph "My Site Settings". Most of the things you have to do, will be located in this paragraph, though not everything.
A good first step is to check out the default settings. So choose "Setup My Sites" and see what is alreay in there. The three most important things here are:
My Site Host
Personal Site Location
Site Naming Format
For us to run through the complete workflow, let’s say these settings are not to your liking and you want to change them. What steps do we need to take to change the entire setup. See more here => Blog – SharePoint 2010: Activating My Sites