The adverb 以 is used to indicate which way or how to do an action.
Nouns or noun phrases that are placed after this preposition answer the question “how?”.
Scheme
以
noun/noun phrase
how?
verb
Pay attention
A noun phrase is a phrase in which the main word is a noun.
Examples
经理您放心,我一定以最快的速度完成
Don’t worry, director! I'll finish as soon as possible