Donorbox to Salesforce Zap not creating contact or connecting opportunity

Hi all,

I have used zapier very lightly in the past and mostly from zaps someone else has set up. So I need some support and after hours of trial and error and googling, I am asking you.

I want to create a zap so when our nonprofit receives donations through donorbox (our online platform) it 

1.  Searches SF to see if the contact already exists 
2. If not creates a contact
3. Creates either a lead or an opportunity connected to the contact

I tried this yesterday and got half of it right but it kept creating an opportunity but not connecting it to the contact (but rather to an account and then not having the primary contact connected which is important).   It will also search for contact but then only give me the option to create an account, not a contact.

When in the account section when I say create record if none found, It asks to choose account info but will that mean all future donations will go through the account I select or is it just an example?

When I tried to create a lead instead of an opportunity it would important the name etc but not the donation which is also very important. 
Finally, what do I answer to the question: Should this step be considered a "success" when nothing is found? If I want it to create the record if nothing is found?  Yes or No?

Any help, even incredibly simple step by step instructions would be great.  I am still learning so I appreciate everyone!