Originally Posted by Mano

Who
"Who" is a subject pronoun like "he," "she" and "we" in the examples above. We use "who" to ask which person does an action or which person is a certain way.
Example
Who made the birthday cake?

Whom
"Whom" is an object pronoun like "him," "her" and "us." We use "whom" to ask which person receives an action.
Example
Whom are you going to invite?

Whose
"Whose" is a possessive pronoun like "his," "her" and "our." We use "whose" to find out which person something belongs to.
Example
Whose dog is barking outside?

As far as
"As far as" is more likely to be used in contexts where you're trying to be helpful, but you're (often, somewhat apologetically) pointing out that what you think may not be totally accurate

Further
uses of further is something that is a longer distance away or something that happens that is in addition to what has already occurred.
We need to discuss this further.

Furthermore
furthermore is used to add more information to what was already said or written.
Example
We believe that the project is possible. Furthermore, we believe that we can do it within a few months.

and sorry for your last question because i'm also a beginner not a senior because i am in the process of learning