Ok, so I've noticed a lot of people having difficulties with attachments.
To make it simple:
You're attaching them to the post, but not specifying where to insert them into the post.
First: click the "choose" button in the bottom right:
Second: select your attachment to upload.
Third: click the green upload button.
Fourth: click "manage current attachments", directly above the choose/upload buttons, then click the green plus arrow on the far left. This will add your attachment anywhere in your post you desire, at the bottom or the top, or in the middle.
If there's anything else beyond this, please don't hesitate to send me a PM.