The principal activity in Granada are the processions.

Each church has a wooden platform structure which is adorned on top with a statue of the Jesus or the Virgen Mary.
The structure is carried around the streets by lots of hidden people underneath.
They are instructed how to move by someone who bangs the side of the platform with a stick.
The platforms move quite slowly and take a long time to do different routes around the city.

The platforms are followed by a musical group with many brass instruments playing mournful Easter music.

The biggest procession is the one on Wednesday night which goes to the Sacromonte abbey.
An interesting one is the silent procession which goes through the Albaicin in candlelight accompanied buy a gentle beat of a drum. That is on Thursday night.

There is more information about the processions and the different routes here
https://granadamap.com/santa/index.htm