并 and 并且 — emphatic denial and adding on

The rule 并 + 不/没 = a CONTRADICTING negative: it pushes back on what the listener assumes.
他并不知道这件事。 = He does NOT know — contrary to what you think.
并 only stands before 不 and 没, never before a bare verb.
并且 = moreover — adding a second clause in the same direction: 他学习好，并且很热心。
Joining two verbs with one subject is 并 too: 讨论并通过了这个计划。