vanish command

[true dome]

you are close, except:
1️⃣ player refers to the player that ran the command, so it will never be false
2️⃣ You did not specify a <player> argument in the command so the vanishing will only be done for the player that ran the command
3️⃣ Your indentation is wrong; you need another for the third line, two more for the fourth, one more for the fifth, two more for the sixth, and three more for the last

if your line starts with if or else if:
that line needs to end with a colon : and this line needs to be indented