Below are the steps to create Site Collection through Central Administration:
1. Login to Central Administration.
2. Go to Application Management –> Create Site Collection.
3. You will see the below screen.
a. Web Application section, if the required web application is not automatically selected, choose the web application on which you want to host your site collection from the drop down, by clicking Change Web Application. Select the web application.
b. Title and Description section, you can also change them later through site collection settings.
i. Title:Type the title of the site collection
ii.Description:Type the description of the site collection.
c. Web Site Address: This will be the URL of the site collection.
d. Template Selection: Select the template that should be used to create the site collection.
e. Primary Site Collection Administrator: Type the user name in the form of domain\username who will be the site collection administrator.
f. Secondary Site Collection Administrator: Type the user name in the form of domain\username who will be the secondary site collection administrator.
g. Quota Template: Select a quota to manage your site collection. You can also choose No Quota if you are not managing quota for your site collection.
i. Click Ok.
Your site collection will be created. It might take few minutes for site collection to be created. Once done, a page will display the URL of the newly created site collection. Access that URL and you will login to the Site Collection.
