list-set! Wrong type argument in position 1 (expecting mutable pair)

[mbcladwell@stihie.net]

Hi,
One shortcoming I find working with Guile is the limited number of  
examples of how to use code. Consider list-set!. The only reference in  
the entire Guile manual is the definition in section 6.6.9.6 List  
Modification. If I google I find  
https://docs.racket-lang.org/reference/pairs.html which gives me the  
example (list-set '(zero one two) 2 "two") ==> '(zero one "two") which  
is what I deduced from the Guile manual.  If I try something similar  
in Guile:

scheme@(guile-user)> (list-set! '("zero" "one" "twooooo") 2 "two")
ice-9/boot-9.scm:1669:16: In procedure raise-exception:
In procedure set-car!: Wrong type argument in position 1 (expecting  
mutable pair): ("twooooo")

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
            1 (list-set! ("zero" "one" "twooooo") 2 "two")
In ice-9/boot-9.scm:
1669:16  0 (raise-exception _ #:continuable? _)

Could someone provide me with an example of how to use list-set! ?
Alternatively what I really need is how to modify a specified element  
in a list.
Thanks
Mortimer