What should I do to comply with my funder’s data management requirements?

That depends on the funder. Often, you need to address data management in your proposal and write a more elaborate data management plan once you have been awarded the funding. Usually, you cannot start your project without approval of the data management plan by the funder. You can find more information about the requirements of several important research funders here. Note that it is always a good idea to write a data management plan before starting a research project and update it during your research project.