What do I need to start filming?

I have a camera, well not the best. but what else do I need like video editing software, where can I get microphones so sound quality is better, and where can I get special effects software? and is there anything else I need? I'm only 15 so don't expect me to have a giant budget. if you know safe sites that I can download this stuff I'll be happy to try it out. just don't get my computer a virus haha.