The official dock for the device won't be available at that time, but the first orders for the Steam Deck will begin on Friday.
Valve said in a post that they are looking forward to getting the official dock for steam deck into customers.
There is a description on Valve's Steam Deck website of the official dock, but it hasn't been shared with the public. You don't need Valve's specific dock to use a powered USB-C hub, according to the company.
It doesn't sound like your games will run better if you play them while docked, according to Valve's Steam Deck FAQ. The company says that steam deck runs at full performance in portable mode.
There was a reminder about the order roll out for launch day. The first group of reservation holders will receive an email on Friday, February 25th at 1PM. We will let the next person in the queue know if they cancel or do not purchase in this time frame.
If you want to know when you will be able to order one of the devices based on your place in the reservation queue, check the Steam Deck website.