For pictures:1. Go to an image hosting website. Examples:
-ImageShack
-Photobucket
-TinyPic
2. Upload your image(s).
3. Get direct links to the image, usually the links will end in .png, .jpg, .gif etc. You can also get a "forum code" or "BBC" link, where the link will be surrounded by IMG tags.
4. Copy/Cut links.
5. Paste them into a post and if they don't already have IMG tags, highlight the link in the post.
6. Click the IMG tag button (

). If the link already contains IMG tags, don't do it again.
7. Click preview to see if you picture shows up.
8. Repeat steps 2-7 until it works if necessary.
If you want to allow people to download it, use the forum uploader under Additional Options, or:
1. Go to a file hosting website. Examples:
-Mediafire
-Box
-Will Host for Food
2. Upload your build.
3. Copy link.
4. Paste in post.