To copy a DNA for a character from a Pastebin link and use it in Crusader Kings 3's Ruler Designer, you can follow these steps:

to open the page containing the DNA code for the character.

Highlight and copy the entire DNA code for the character from the Pastebin page. You can usually do this by selecting the text and pressing Ctrl+C (or Command+C on Mac). You can also click on Copy Raw.

- Launch Crusader Kings 3 on your computer.
- In the main menu, click on "New Game" to start a new game.

- Choose the start date (either 867 or 1066) that you prefer.
- On the world map, select the historical ruler that you want to replace with your customized character.

- After selecting a ruler, look for an option that allows you to create your own ruler. This option should be available when replacing a historical ruler.

- In the Ruler Designer interface, look for the section related to appearance customization.
- You should find an option to paste the DNA code. Click on this option.

- After pasting the DNA code, confirm your choices.
- You may need to make further adjustments to other aspects of your character, such as traits, attributes, and skills, as mentioned in the provided information.

- Once you are satisfied with your customized character, finalize your choices.
- Start the game with your newly created ruler.

DNA[pastebin.com]

To look the same as when you play in the year 867, set the age to 19.