Here is an extremely short how to allow basic auth to an apache2 web server.

The prerequisites are (in my case):

Step 1: Install appropriate packages.

apt-get install subversion

apt-get install websvn (this will be stored in /usr/share/websvn)

Step 2: Add basic auth to apache2 configuration

Edit vi /etc/apache2/sites-available/default

Step 3: Create a directory ouside of apache2 for password file

Step 4: Add a new user (for basic auth)

Step 5) Create a test directory in the webserver such as /var/www/test

Step 6) Add a .htaccess file there
Add this content to that file

Step 7) Add a simple index.html file in the directory
Add content to index.html

Step 8) Restart apache2 /etc/init.d/apache2 restart

That's it

If you browse to localhost/test you shall be promted to enter user testuser and the password you used when creating the password file in step 4