The planets are orbiting the sun continuously, meaning their positions are changing. Jupiter, Mars, Venus and Saturn are the easiest to see when they are visible, as they appear very bright. Mercury can be seen, but is too close to the sun usually to be clearly seen. The others are very far away, so not very bright. Currently, Jupiter is best to see and easy to find. It can be seen as a very bright object towards the south, for a few hours after sunset. Regularly check out Heavens Above, which is the site linked to below, which will help you to find the different planets and much more in the night sky.