“And alongside the territory for the priests.” When we put the three sections of the holy offering area together, we can see that the priests have the central section that contains the Temple, and the section with the city of Jerusalem is the south section, so the section for the Levites is next to the section of the priests and on the north side of it (see commentary on Ezekiel 48:8).

“length...width.” In this context, the length is the east-west measurement and the width is the north-south measurement.

“25,000…10,000.” 25,000 royal cubits is just over 8 miles (8.12 miles; 13.06 km), while 10,000 royal cubits is roughly 3.25 miles (5.23 km).

[For the measurement of the royal cubit, see commentary on Ezekiel 48:8.]