I believe you decline everything and leave the personal policy information blank. If there is damage to the car, you start the claim process with Chase's insurer and let Silvercar know that you're covered through that.

Keep in mind, if you don't have your own insurance or some other umbrella insurance policy that would cover you, the coverage from the CSR is only for damage to the car itself and does not cover liability. I believe (but am not sure) that car rental companies are still supposed to cover your liability up to state minimums, but the amount is quite limited. For this reason I always decline the CDW but pay for the supplemental liability as I don't own a car and don't have my own insurance coverage.