Adverbs serve two major roles: they can be integrated into an element of the clause, or they themselves can be an element of the clause. In the first case, the adverb serves as a
modifier; in the second case, the adverb is an
adverbial.
When adverbs are modifiers, they usually modify an adjective or another adverb.
There are no (adverb) modifiers in your sentences.
The adverbs serve typically adverbial functions.
1. Dad drove backwards into the garage last night.
2. Dad drove carefully into the garage last night.
In #1, there are two circumstance adverbials:
- backwards (manner) (both backward (AmE) and backwards (BrE) work)
- into the garage (direction)
In #2:
- carefully (manner)
- into the garage (direction)
- last night (point in time)