I don't know how things are in other countries, but ...
I don't know how they do things in other nations, but ...
「他の国がどうなのかわからないが、…」は英語で次のように表現できます。
ーI don't know how things are in other countries, but ...
ーI don't know how they do things in other nations, but ...
例:
I don't know how things are in other countries, but we don't really do many public protests in Japan.
「他の国がどうなのかわからないが、日本ではあまり多くの抗議活動をしない」
public protests で「抗議・抗議活動」
ご参考まで!