Information on the type of support governments can provide to their nationals in the wake of a kidnap incident can usually be found on the foreign affairs department website. For instance:
The UK’s Foreign and Commonwealth Office has published Support for British National’s Abroad: A Guide
Australia’s Department for Foreign Affairs and Trade’s guidance is in their Consular Services Charter and in their Smart Traveller guide.
Global Affairs Canada’s guidance can be found on their Consular Service Charter
Policies on hostage-taking and resolution vary from government to government, and the information can be found in policy and position papers or statements made by elected officials. It is essential to know a government’s policy in order to understand the parameters within which any resolution can take place. For instance, in many countries, it is illegal for anyone (individual or organisation) to pay a ransom to a proscribed terrorist organisation.