If you are using montages for the attacks then this video should have the info you need. It’s a bit out of date but you should be fine.
If you are doing it with animations and your state machine then you should blend the attack animations with the locomotion blendspace using the “layered blend per bone” node (as suggested). You may also want to use a “blend by bool” node so you can turn the layered blend on when attacking and off when the attack is finished (depending on how your anim BP is set up).
Hopefully you’re using montages. It’ll be a bit easier to deal with.