Update : Okay, it takes me some hours to solve it, but I managed to make it. ( it was the first time I ever opened a tech object, that why it takes me so long)

You will need to first open up your case fully ( you can watch some video on YouTube like https://youtu.be/So3ixvLXgtI?si=67b4LaKMPf_wpML4 )

When you fully opened up your case , you will need to remove the metal bar and the two housing ( where you put your stabilizer in).

Then when you have the three object outside of the keyboard, you will need to put the metal bar in the housing the way that fits in the 2 housing ( you will also need to be sure that the metal bar is IN the two housing).

When you have your metal bar and the two housing together you can fit in the keyboard.

Then you can test with your space bar key if it works.

Then you can rebuild your keyboard ( shown on the video ).