> can you open raw file with this software if not what do you do to open them
No, PSA SE does not have RAW support. As free software, it is intended for beginners with digital imaging, for whom RAW is not an issue.
You probably received some software with your camera. Another options is to buy Photoshop Elements, which does have RAW support. Just one note: every make of camera [and even different models] has its own RAW format - you might want to check that your specific one is supported.