According to Bezos, the money be used to help scientists, activists, NGOs and anyone who can offer something of value to reduce the impact of climate change. According to a person who is close to the fund, which talked to the Verge, the fund not engage in private sector, but it will focus on charitable giving.
Grants will start going around this summer, but currently there is not much information on how to apply and the application process itself.
As you might already know, the net worth of Bezos is $130 billion, so $10 billion is a huge chunk of his worth. In 2018 he did launch announce free non-profit preschools to be build in love-income communities.