Good day 
nateinoh,
I see you are already versed in SharePoint and you want to add a form to a list that you already created. Your form should have the ability to submit data to your SharePoint Library, what I would do is to put a button to your form then configure the data connections to your SharePoint List. Then go to "Tools" Menu -> "Submit Options and click "Add", a window appear where you will put in your List URL for SharePoint Library. After you finish the previous step, right click on the button you created then choose "Button Properties" then choose "Submit" on the "Action" dropdown field. Then you need to publish a form to your SharePoint Server, before you can add, modify or save data in your SharePoint List. On the "File" menu click on "Publish" choose "To a SharePoint server...". Copy the URL of the SharePoint Library and place it in the location box choose "Document Library" click next until finish.
Open the SharePoint Library you published the form click on "Add document" the form will open in a browser or InfoPath filler, click on the Submit Button we created earlier and the form will be saved on your SharePoint Library. Let's say you have fields where you can enter a name, address, email, etc on your form you just have to put in data then click on submit to save it on the library. Once saved there will be files on your SharePoint Library and when you click one of the files it will open the form with the data you entered previously and when you want to edit it just enter new information then click on submit to modify the data on your SharePoint library.
I hope it help you.