Here's the top of the PSU shroud with the various mounting holes circled.
Circled in grey, you have mounting holes for the SSD trays that are, by default, in the rear of the motherboard tray. But, if you want, you can move them up here.
The six holes circled with yellow are the mounting holes for the standoffs for a GPU vertical mount. There are 3 positions for a vertical GPU mount and the mounting holes for the standoffs are 120mm apart.