To talk about what you need in Spanish, you can use the verb 'necesitar'. It's a regular -ar verb, so it follows the standard pattern you already know. You can use it with a noun, or with another verb in its infinitive form.

To say you need a thing, use 'necesitar' followed by a noun. For example, 'Necesito un libro' means 'I need a book'. 'Ella necesita agua' means 'She needs water'.

To say you need to do an action, use 'necesitar' followed by a verb in the infinitive. For instance, 'Necesito estudiar' means 'I need to study'. The second verb always stays in its '-ar', '-er', or '-ir' form.