The T1N manual describes #1 as being next to the steering column and #2 under the driver's seat. They refer to the one on the positive battery terminal as a power distribution block. There is a much better post about this by Doktor A somewhere here but I could not find it.
Fuse block number 1 is -on- the steering column. Turn the quarter-turn screw head to make the slot level,
then pull the cover off from the top (there are two side-snaps). There's a layout diagram inside the cover.
Fuse block number 2 and the Fuse/Relay Panel are behind the removable panel on the outside of the driver's seat pedestal.
That panel also has the fuse layout diagram unique to -your- vehicle. Go copy it.
The remainder of the relays and stuff are under the driver's seat, accessible by unscrewing the retaining screw at the rear of the cardboard lid,
then sliding the seat back and lifting out the cardboard cover.
See attached: Power block off the battery, Fuse Block 1 under the steering column, the rest under the driver's seat. Also, DO NOT trust the allocation of the fuses shown on these sheets. Many Sprinters are idiosyncratic - especially Fuse Blocks 2 and 3.