Problem with understanding the action of いる in 決まった場所にいる代わりに

In a recent article 仕事で外国に行く前にＰＣＲ検査の予約ができるようにする from NHK Easy Japanese I found this sentence, (which I give here in a bit abbreviated form):

[...]着いてからしばらくの間、決まった場所にいる代わりに、PCR検査で[...]ウイルスがうつっていないことを証明する必要があります。

I believe the sentence could be translated roughly as

"It's necessary to verify with a PCR test that the virus didn't hit INSTEAD of testing after arriving at the respective locations." 

But I have trouble to fully understand this sentence, because I do not know where the いる from 決まった場所にいる代わりに is connecting to.

Thanks a lot!