Please refer below instructions for Donation Widget Configuration on the Checkout Page for Theme 2.0 & Theme 1.0 both.

→ Add this part of the code from donation.liquid to your checkout template

 <div class='donation' page='cart' >
      <div class='donation_loader'>
      <img width='130' height='130' src=' https://easydonation.zestardshop.com/image/loader_new.svg'/>
    </div>
</div>
<script src=" https://easydonation.zestardshop.com/js/donation.js" defer></script>

Note: If you are using Theme 2.0 then you need to add donation.liquid file inside your theme, please get in touch with us to get it done via Live Chat or send us an email at support@zestard.com.