Deploy Resonators on neutral (grey) Portals to capture them for your Faction:
  1. Get within 40m range of a nearby Portal
  2. On the Map screen, tap the Portal to open the Portal Details screen, then tap the Deploy button
  3. Tap DEPLOY eight times to deploy eight Resonators and fully resonate the Portal
Protip: Resonators are deployed based on your current distance from the Portal core. Stand 40m away from the Portal to deploy Resonators in a wider array; stand 1m away to deploy Resonators densely clustered around the Portal core (like a pineapple).

Resonators are level-restricted items that range from Level 1 to L8. For example, L2 Agents can only deploy L1 and L2 Resonators, while L8 Agents can deploy L1 through L8 Resonators.