Conditional: Regular 'ER' Verbs
Spanish: Cambridge International GCSE, topic 10.2.2
ER Verbs in the Conditional Tense
To form the conditional tense for regular verbs, take the infinitive without removing the infinitive ending and add the conditional endings for each person. The endings are exactly the same as the imperfect ER, IR endings. Here is the example with 'volver':

Volvería - I would return

Volverías - you would return

Volvería - he/she would return / you would return (formal)

Volveríamos - we would return

Volveríais - you would return (plural)

Volverían - they would return / you would return (formal plural)
Test yourself on Conditional: Regular 'ER' Verbs
'Comer' is a regular ER verb in the conditional tense. How do you say 'they would eat' in Spanish?
¿Cómo dirías 'I would be' en Español?