My problem is I know how to do electron configuration, but I don't know how to write a noble gas notation for all elements because I'm a little bit confused about it.

For example: noble gas notation for
K is [Ar] 4s^1
Sc: [Ar] 4s^2 3d^1
Ga: [Ar] 3d^10 4s^2 4p^1
Rh: [Kr] 4d^8 5s^1
Tb: [Xe] 4f^9 6s^2
Hg: [Xe] 4f^14 5d^10 6s^2
Rn: [Xe] 4f^14 5d^10 6s^2 6p^6

how do you get all of that? Is there any rules that I need to remember? Thank you!!!

You have to just check that your element is next to which noble gas
Like K is after the Ar noble gas period
K has 19 electrons
18 will be filled exactly as in Ar
and one will go in the next shell 4s1