The first step when conjugating infinitive verbs is to remove the infinitive ending -ar, leaving you with the stem - in this case, bail.
The next step would then be to add the verb ending which matches the subject. In present tense for bailar, they would be:
Yo bailo
Tu bailas
El/Ella baila
Nosotros bailamos
Ellos/Ellas bailan
Answer:
Drop the -ar from the infinitive, leaving the stem bail.