Thee rest days is once a week , on (Friday, etc).

休息日每周一次，在（星期五，或其他日）。 。

youdao

I visited a friend of mine on the Friday of last week.

上周的星期五我去拜访了一位朋友。

youdao

I visited a friend of mine on the Friday of last week.

上周的星期五我去拜访了一位朋友。

youdao