Usages of nos
Os amigos estão nos cafés.
The friends are in the cafés.
As chaves estão nos bolsos.
The keys are in the pockets.
A formiga está a andar nos talheres que a gente trouxe.
The ant is walking on the cutlery that we (informal) brought.
Elon.io is an online learning platform
We have an entire course teaching Portuguese (Portugal) grammar and vocabulary.