I have made threads which will guide you through adding pictures and links to any of your posts. I hope you will take a look and learn to do this. You will have fun with it I know. Your photos have to have a url associated with them to put them on the forum. Uploading them to a place like Photobucket will give them the url they need.
Your videos can only be shared by linking to them. You Tube and I also believe Photobucket have Video sharing opportunities. Use these services or another of your liking to get a url to share on the forum.