First Appeal is sent to the First appellate authority of the department, who is generally a senior member of the same department, when information initially asked is not answered or insufficiently answered.
First appeal can be filed 30 days after the delivery of your application to the required department. In some cases when the fresh RTI application is sent to the Assistant PIO this period is extended to 35 days. If after the expiry of the required period you do not receive a reply or are not satisfied with the reply you have received you need to file a First Appeal within 30 days.
To do so through RTI Nation.com you need to follow the normal procedure by clicking on the "Submit RTI Application" link. In this form you simply have to select "First Appeal" under the type of application being filed. The fees of this through rtination.com is Rs. 150.
You can also choose to file this manually with the department's first appellate authority.