You can upload images to the file galleries. Please create a new gallery for each page / topic.
When inserting images (through the image / images button in the first row of the editor) you can choose if there should be displayed a small thumbnail (which the user can click and view the image in a bigger size) or you can insert it in the original size. It depends on the context you are using this image.
If the information you want to add doesn't fit into the links under "Hot Links" you can create a new "Topic" and link it in the "Hot Links" menu. You can edit the Hot Links menu here. But think carefully about the question if your topic doesn't fit. If neccessary then change the Topic name to a more abstract one to prevent a topic flood.
Please use an existing row as a template. Especially the line breaks in a row are very confusing (at least for me). If you know a better solution (Tikiwiki-wise) then please let me know.
Feel free to change the manual. It is outdated and every new information will be a good information.