Select your tree from the Trees menu
Look in the top right corner of the Ancestry web page for the Find Person button
You can either search for a particular person or browse the List of All People
If you are looking at an individual profile, the Find Person button is at the top left of the web page
To add photos to the page, choose the Gallery option when viewing an individual profile
In the Gallery you can either use the Upload Media button or click Add and choose the Upload Photos option
This is also where you can upload a story from (say) a Word document or create a story for any individual
You can choose either option to upload files, they both open the same dialog box where you can browse and find the files you need for this individual. Note that the files will be visible to everyone on Ancestry.com.au if you tree is Public. If you set your tree to Private, no-one will be able to view your tree
You can update as many or as few details as you need, giving the image a Title and stating the Type of Media is a good starting point nd if you know the Date & Place enter those as well. You can also ad a description if you wish.
If there is more than one person in the photo from your family tree you can use the Linked to option to add this photo to the gallery of other individuals which means you don't have to upload them for each person.