Make sure you have enabled the camera by

sudo raspi-config

(If you don't know how to do this take a look at Log 2.)

raspistill -o cam.jpg    # take a picture with the raspberry picam
raspivid -o video.h264 -t 10000    #record a video (for 10s) with picam

Use

ls -l

command to verify "cam.jpg" and "video.h256" are there.

pcmanfm &

command to open the documents folder of the raspberry pi

[VISUAL!]

there should be the picture you've just took (named as cam.jpg) double click on that to open the picture

also the video (named as video.h264) that you've recorded is located in the same directory.