Hi folks, some help would be greatly appreciated. I'm attempting to create a homebrew sorcerer subclass similar to the Bladesinger wizard to use in my campaign. I've figured out most of the martial combat stuff, but if I wanted a lvl 6 feature that gave the character the Mutliattack/Extra Attack feature, how would I do that? I'm assuming it would be in the Create Modifier section, but I just can't find anything. Thanks in advance! :)

Extra Attack

Modifier: Set->Subtype: Extra Attacks->Fixed Value: 1

Monsters get multiattack, PCs get Extra Attack and they don’t get it until 5th level. If you want to include Extra Attack as a racial trait, it shouldn’t hit until 5th level. And remember, it won’t stack with the Extra Attack class feature, so if they take your race and also take a class that grants Extra Attack at 5th level, they won’t get both, only the one Extra Attack. Alright, sermon over. 

How to do it? The exact same way I already explained in the post directly above yours.