By default, DRS works at the Fully Automated automation level. You can, however, choose to set it to Manual or Partially Automated. Although the names of the automation levels are self-explanatory, there are a few additional differences:
Fully Automated: This automatically carries out VM initial placements and migrations
Partially Automated: This does VM initial placements automatically, but migration recommendations are displayed to the administrator and are not performed until the administrator applies them
Manual: This displays both the initial placement and the migration recommendations to the administrator; it requires the administrator's approval to be applied
This is done on a DRS-enabled cluster, so make sure you have access to the vCenter managing the intended ESXi cluster.