1Not for the faint of heart
There are a LOT of components on this board. I'd not recommend attempting to assemble the board on your own unless you possess a lot of time or a lot of skill. I had my boards assembled from JLCPCB where I had them manufactured.
That being said, there aren't any real gotcha's to be had. The terminating resistors for the qspi lines (2 for each line next to each mcu) are 1k but can be adjusted if you want to troubleshoot getting the qspi bus to run at >90MHz (e.g. 133MHz).
When plugging in the pcb to your n64, the face with all the components should be facing AWAY from you. The board is also labeled with "front" and "back". With "back" being the side with the components.