Sansa Clip - saying I dont have space when I try to add songs?

I have just got a sansa clip and I have tried to add a block of songs, which are 1.5gb (clip is 8gb) but it says there is not enough space? Anyone else have same prob? Dont know what to do!

Format the clip.  You will lose any content on the device.

Unplug the device.

Go to Settings>Format> select Yes