On this page of the Cyberpunk 2077 game guide you will find a detailed walkthrough of the Sweet Dreams side job.
As you traverse the market in Japantown (sub-district of Westbrook) you may encounter Stefan, a braindance salesman. The resulting conversation with the salesman will initiate the Sweet Dreams job.
Talk to Stefan
Stefan claims that he has something special for V if they can afford the steep price, as the braindance costs 16,000 Eurodollars. While you may attempt to play the recording on your own equipment, it's guaranteed not to work.
Speak to Stefan and ask to borrow his equipment. You will get a notification about a money transfer, but you might encounter a glitch and the cash won't be subtracted from your account. Follow the salesman to a nearby room to play the recording.
Escape the Scavengers hideout
Moments later, you will wake up without your belongings in the Scavs hideout, which you should remember from the main job The Rescue. However, you should recover your items before you escape the hideout.
Leave the bathroom and get the first opponent from behind. Grab him, then drag him into the bathroom and quietly dispose of him. Take his weapon - just in case the situation gets heated.
Head to the next room (the door is on the left side of the bathroom) and silently deal with the opponent standing in front of the computers.
Now go to the room on the left - you will find another Scavenger there. Stealthily dispose of him, then go through a small hole in the wall on the right and eliminate the enemy who is actively patrolling the entire floor of the building.
Return to the room with the computer and make sure you're ready to enter the main room. You will find your items in the cabinet on the right. You can quickly approach the cabinet, reacquire your things and go back to hiding. This way you will most likely avoid the attention of your opponents.
You can continue onwards using stealth or by eliminating the remaining enemies in the usual way, i.e. using your favorite weapon. When you enter the main corridor, turn left and take the elevator to street level.
After leaving the Scavengers hideout, head straight to Stefan to register a complaint. During the conversation you'll get to decide what to do with him, however, regardless of your choice, the reward for completing the job will be exactly the same - XP and Street Cred.