en_tn_condensed/num/21/30.md

we have conquered

Here "we" refers to the Israelites who defeated Sihon.

Heshbon is devastated

"We have devastated Heshbon"

Heshbon ... all the way to Dibon ... all the way to Nophah ... to Medeba

These are all places in Sihon's kingdom. This means the Israelites destroyed Sihon's entire nation.