If you are a first year Language Assistant in Spain and are applying for your first TIE (Tarjeta de Identificacion de Extranjero), you would need to fill the form to be able to pay the fees for TIE application. Here, you have the guide to help you with the process.
A new Auxiliar or student in Spain? Here you have the guide to help you appy your first TIE card in Spain. Guide to fill form Ex 17