1.
You must have ssh(secure shell) or command line access to your server to continue with this tutorial.
2.
SSH into your server and change to the webroot directory. Then type:
wget http://textpattern.com/file_download/37/textpattern-4.0.5.tar.gz
3.
Now unpack the downloaded file.
tar -xvzf textpattern-4.0.5.tar.gz
4.
Copy the contents of the unpacked folder to the webroot.
cp textpattern-4.0.5/* ./
Make sure that ../ is the path to your webroot from your current folder position.