You can make your own yeast.

You can buy dried yeast.

4. You can put a little salt and sugar when fermenting.

5. If it is sour, you can add a little alkaline noodles.

6. Knead the dough.

7. Wake up the kneaded dough.

8. Steamed steamed buns If fermented steamed buns use hot water, if they are not fermented, use cold water.

9. Oil the grate or use steamed cloth.

10, steam for 25 minutes.