Download the latest version of Joomla! from the provider's website.

http://www.joomla.de/

Unzip the file (e.g. Joomla_3.2.0-Stable-Full_Package.zip) to a location where you can find it again.

Next, open your FTP client (e.g. FileZilla) and connect to your webspace with the FTP access data, then search for the folder you have unpacked. Now select the folders and 

files from Joomla! which you can find in the unpacked directory (e.g. Joomla_3.2.0-Stable-Full_Package).

Copy folders and files to the selected main directory, which is normally /htdocs. Wait until the transfer is complete.

Create a MySQL database and remember the database name,

login name and password.

A description of how to create a MySQL database can be found at 

following link:

How do I create a MySQL database?

Now open your browser and enter your domain name. If everything went well, you will find a page here that looks like the one in the picture below. Here you can first enter the desired title of your website under the item Name. 

The fields on the right are important here. Here you enter the data for the future administration of your 

Website, i.e. an existing e-mail address, a user name and the password you would like to use in the future.

To proceed to the next step, click on "Next".

Enter your MySQL data in the following window. The server name is always localhost. User name, password and database name are specific. The database type and table prefix remain as they are. When the data is entered, click "Next" again.

If you would like to install sample data, click on the point in front of the desired data under "Install sample data". In the lower area you can select whether the settings and, if applicable, your password for Joomla should be sent to you by e-mail.

Once you have selected everything, click on the "Install" button in the upper right corner.

To complete the installation, click on the button "Delete installation directory".

You have now installed Joomla! and can log in at any time under your domain name plus "/administrator" behind it (e.g. http://www.mustermann.de/administrator) to make configurations on the site, or call up your domain name to view the site.