Using attachment to attach a sword to a player arm?

So I'm trying to make an RPG game. I heard there was a new thing added to Roblox called Attachment which attaches hats (and probably tools) to a player. So basically I have made a sword and I want to make the player hold it without using a tool. The arm which holds the sword should be in the same normal position and the breathing/walking animation should still work normaly. I'm not even sure if that's what attachments do so If I'm wrong and you know how to make the sword be attached with the arm, please help me out.