I purchased the following: Schiit Modius Schiit Valhalla

My understanding is that they come with their respective power cables that plug directly into the wall… Is that right?

Otherwise what would I need to connect them together and to my phone if those cables don’t come included?

Finally, would the Sennheiser 800S be cable to plug into it with the included cable?

Thanks, I’m new to all of this so I’m trying to learn and make sure I have all the required gear!