To create a new form first go to the Freeform plugin in the sidebar.
Once you are in the Freeform page click the red button + New Form.
On the right side you need to fill out some details about the form in order for it to work correctly. The Name is required as is the Handle. The Handle will be auto-generated from the Name.If there is an existing form with the same handle you will need to change this to something unique.
All other options should stay with the defaults. You can optionally add a note about what this form is for in the Description/Notes field at the bottom right.
Switch to the Notifications Tab on the right and select the default email notification. Now add any email addresses form submissions should be sent to; one address per line.
Adding fields to your form is simple. Select a pre-existing field on the left side and drag it into the form. You can add as many fields as you like and then re-order them as you like.
When you select a field in the middle you can drag/drop it up and down or next to other fields. Additionally on the right side there will be options for each field. You can change the label, add instructions, or add new options for checkboxes/radio fields.
There are two options for creating new fields. You can add a new field from the create a form page by clicking the Add New Field button on the left. Or you can go to the fields option on the far left.
I find it is easier to create the new field in the fields option on the far left. Go there create a new field and fill in the options and then add it to your form.
Finally don't forget to add a submit button to the bottom of the form.