Help with coding!

I have no idea how to add my simple fields to the code. I read the instructions, but it is greek to me! The post in question is http://www.topniksellswinnipeg.com/test-jt/. I have about 10 fields created and I just need them to show up on the post now. Please help!

https://wordpress.org/plugins/simple-fields/