Depending on the version you have in the effects menu, choose "display duration" and enter the time in minutes:seconds:frames. Page 167 on the manual that I have.
Duration time for each photo and placement on the timeline for the order. Probably the time for the first photo must be shorter. Click to select the first photo, click using the right mouse button and select change the photo length you can use the slider or type in the box 00:00:10 last box.
In photo story you only have 4 tracks available to work with. You can place your photos in timeline mode on the tracks then use "size and position to place them on the screen, but with only 4 tracks assuming 1 for audio and 1 for a title, you are really only going to be able to show 2 or 3 (if you don't use a title) using this product. Movie Edit Pro is much better suited to what you are trying to do because you have access to many more tracks (99).