You may need to upload a link or a media content, such as a picture or a video, to better explain your post.
In this case, when creating or editing a post, you have an options bar above with many different choices.
To insert a link:
Insert a Picture or a Video from a website:
In a very similar way to the links, you can also share a picture from any web address.
Upload an image from your computer:
If you want instead share your own picture, you can simply upload it from the button Upload an Image below each post editing section.
It is really simple:
The procedure is currently available only from Computer or MAC. Through a mobile these functions are not yet supported.
However, you can still share a link: just copy its url and paste it by touching for a few seconds a blank part of the writing window.