For nouns and adjectival nouns (形容動詞), the ば conditional is formed by attaching the appropriate form of the copula, e.g. ならば for だ, or であれば for である. However, ならば is not frequently used, and the usual form is なら.
For so-called consonant stem verbs (五段活用動詞), the ば conditional is formed by attaching -eba to the stem, and for the vowel stem verbs (一段活用動詞), we attach -reba. For the irregular verbs we have:
Finally, the adjectives (形容詞) form their ば conditional by attaching -kereba to the stem.
(In the traditional analysis, these are all explained by the rule of attaching ば to the conditional stem (仮定形). Some of the other conditionals are, morphologically speaking, special cases of this.)