1)
To what should they put their hearts?
1.
Malbim: From this day that the Heichal was founded, do not do mere external deeds. Rather, build the Mikdash with intent!
2)
When was "Asher Yusad Heichal"?
1.
Rashi: Now they began to add to the first foundation that they built in the days of Koresh [Radak - when they built the Mizbe'ach].