The conditional is the tense we use to speak about wishes or events which may happen in the future. For example, in English, we might say ' I would like to buy an ice cream' - The 'would' part of this sentence alerts us to the fact that the verb is in the conditional. In French you would say 'Je voudrais acheter une glace'. The endings for the conditional in French are as follows:
- ais, -ais, -ait, -ions, -iez, -aient
So in order to form the conditional you take the infinitive form of the verb eg. manger and then add the appropriate conditional ending. If you wanted to say 'I would eat', therefore, you would say 'Je mangerais'.
I hope that makes sense!