Say if I did not get along with a family member. If I forgive him, can I separate myself from him, like move away from him, and never speak to him again?
Can you move? Of course! Once you are an adult you can live wherever you like. Now, that means you are taking on responsibilities that you might not have had before. You will need a job and a place to live, but both of those things are doable if you are willing to put in effort.
But what seems to be missing is an understanding of what forgiveness is. Forgiveness is the releasing of a person from any obligations to you. It means that you will treat the person as if the bad things he has done to you never occurred. I know you won't be able to forget what happened, but when you forgive someone, you work at treating the person with kindness and respect -- despite the past.
Since this person is a family member, it will be necessary at times to talk with him. There will be family gatherings where you might run across the person. It doesn't mean you have to treat him as if he was your best friend, but it also means you aren't rude.
It is difficult to achieve forgiveness, since it isn't merely words, but it helps a lot when you know that the person you have forgiven regrets what he has done. "Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him" (Luke 17:3). Notice that repentance comes before forgiveness. God is not asking us to forgive people while they remain in their sins. That means that in order to forgive, I must work at helping that person understand what he did was wrong and why. That, too, is not easy, but it is necessary.
Now, everyone won't repent. God would like to forgive everyone (II Peter 3:9), but few are actually willing to change. Still, the effort has to be made. You have to be willing to forgive whenever that person finally does change.
Let's say you have a father to who gets drunk and abusive. Then you need to talk to him about why drinking is ruining your relationship with him. If he doesn't want to give up drinking, then moving out is a practical choice. You keep your interactions with him polite and kind but minimal. Call him to wish him a happy birthday or send him a nice card talking about the good memories that you have of him. When he asks why you aren't visiting more, tell him that you don't want to see him drunk because enough good memories were ruined as it was. Either he will write you off, or he will change. But at least you know that you gave him a chance to change.