Start with eggs:
Keep the eggs warm until they hatch. When they do hatch, you should get something like this:
That doesn’t look like a bird at all! You did it wrong!
Just kidding. You’re fine. Now, feed the chicks:
That looks like a bird! Well done! Now keep feeding it. At 16-20 days old, it should leave the nest (fledge):
You’re done! Haha no. Now you just have to keep feeding it, and also warning it about predators! Being a parent bird involves a lot of feeding. But after a week or so, you can stop feeding it, and it will survive on its own.
*This is a joke; you cannot make House Wrens, you are not a House Wren. (If you are a House Wren, email me ASAP so I can start work on my ground-breaking paper, “Internet access and English language comprehension by a passerine bird.”) These photos are from my nest monitoring, and I always put the eggs/chicks right back in the nest afterwards.
**”Breaking pins” is a term for when the chick’s pinfeathers break through their protective sheaths. You can see the fluff beginning to poke out of the plastic-looking sheaths on the wing feathers in this picture.