Truss Calculator

[Paul]

Brand new member...
Was looking for a plug 'n play calculator for doing truss design and loading.
I am building a small covered porch, at my house, and just wanting to make sure that my hand built trusses will meet the specs of my local building code.
Not sure how the truss calculation tool actually works?
I plugged in some basic info, and hit submit, but I get no feedback.
Can anyone assist me in where I am going wrong?
Thank you,

Paul