There are a number of options and functions in the 400D that are not very intuitive to someone new to a Canon DSLR. You'll need to go through the operating manual to fully understand how to operate the camera and get the best performance from it.
If the camera did not come with a manual, you can download a copy from one of Canon's websites. The following is a link to Canon Asia, select 'support and downloads' and go from there.
Edit: I neglected to post the link. As mentioned, Canon has other sites for documentation but this will get you started in the event you do not have a manual.
http://www.canon-asia.com/
Last edited by dougj on Sun Jun 24, 2007 7:27 am, edited 2 times in total.