503. Misuse of after for afterwards, etc
(X) After we went home for dinner.
(O) Afterwards we went home for dinner.
"After" is a preposition and we must use it with an object.
"Afterwards, then, after that" are adverbs of time and we can use them alone.
504. And the two, etc., used for both, etc
(X) I've seen and the two of them.
(O) I've seen both of them.
Never say "and the two" instead of both. Also avoid "and the three, four", etc.
Say, all three, four, etc.
505. Misuse of and for also or too
(X) Let me do and the next exercise.
(O) Let's also do the next exercise. "or" Let me do the next exercise too.
"And" is a conjunction, and can only join similar forms of speech.
He came and sat down.
We can't use it[= and] instead of the adverbs "also and too".