Bonkey - I'm assuming you are looking for a baby boar? (Your currant boar isn't neutered I'm guessing.I know you got him recently).
Make sure your breeder double checks that your new pig is a boy. Otherwise 60+ days down the line you'll have your own pig family. It happened to me with my first GP .2 girls, one turned out to be male = piglets.
There's a website called barmy4Boars that has got lots of advice about bonding 2 boys.
Introduce them on neutral territory.
Wash the baby to get the smell of his mum off him.
Have a look online about the signs of aggression and know what is 'normal' and what isn't.
I've got 2 adult boars (brothers) that I got from rescue when they were a year old. I've never had a pair of boars so this is a learning curve for us. (I've had 12 previous but only one adult boar)
Ours have little snipes at each other, their heads go up.They circle each other. Our big boar is the dominant one.He goes into a clean box and does a pee to mark.
But the little guy was the instigator of their 'Big Fight'.
They need room,lots of room.
And hidey spaces. 1 each + 1 spare. (We give cardboard boxes with a big enough doorway cut so that they can't trap each other)
We make sure there is space between their food,water and salad bowl so that one doesn't trap the other.
Male GPs go through their puberty (some websites say 4 months ,some 6 months) I missed this 
. But you'll be going through 2 stages of Pig Puberty with the different ages.
You are doing the best thing getting a cagemate for your boy. Your breeder will be able to match-up a boar going by your boys personality and the pigs they have.