Fallout 4: a devilish job - tips & tricks

Fallout 4: a devilish job - explore the museum

You can find the order in the quest overview under "Other" with the name "Investigate the Museum of Witchcraft".

You can get the order from a city guard in Diamond City, for example.
First you have to examine Private Hart's body on site. Here you will find a holo tape that you can play with the Pip Boy.
Enter the museum through the hatch into the basement as the main entrance is locked.
Find a flight of stairs to the ground floor.
Once on the ground floor you will find a copy of Grognak the Barbarian on a table that you should collect.
In the corridor you encounter a wild claw of death. This is a particularly strong mutation in the Death Claw.
Do not take up the fight, but flee outside so that the Death Claw follows you.
Then run back into the laundromat. Here you can find Sergeant Lee's body. You will also find the holo tape you were looking for here.
The Death Claw cannot follow you into the bathroom. So you can always shoot at them and retreat to the bathroom. So you can kill them slowly.

In the holo volume next to Sergeant Lee you will find some information about the Death Claw Egg.

Pick up the Death Claw Egg and exit the museum through the front entrance.
You now have two options for completing the quest.
Bring the egg to the Wellingham robot in Diamond City in front of the Colonial Pub. He'll pay you 200 caps. You can even get up to 500 caps with your persuasion skills.
Alternatively, you can take the egg to his mom. You will find the nest between the Parsons dairy and the Theta reconnaissance bunker. For this, the Deathclaw mother does not attack you and you complete the quest with a good deed and a clear conscience.