How to change Default Input Language Text and Language settings in Windows 7 machines via GPO?

Did you check out this article?: https://social.technet.microsoft.com/wiki/contents/articles/6281.how-to-set-the-keyboard-layout-through-group-policy-gpo.aspx

I will have to change the language to English (Australia) - US. Where should I change in the following code?
Do I have to save the whole of the following as adm file?
PLEASE ADVISE.
______________________________________________________________________________________________
CLASS USER

CATEGORY “Keyboard Layout”
POLICY “Keyboard Layout”
KEYNAME “Keyboard Layout\preload”
PART “Dutch (US-International)” CHECKBOX
VALUENAME “1¿          ; This will become the default keyboard ;
VALUEON “00000413¿
VALUEOFF “00000000¿
ACTIONLISTON
KEYNAME “Keyboard Layout\Substitutes”
VALUENAME “00000413¿      ; Substitute Dutch keyboard layout ;
VALUE “00020409¿           ; for US-International ;
END ACTIONLISTON
ACTIONLISTOFF
KEYNAME “Keyboard Layout\Substitutes”
VALUENAME “00000413¿
VALUE “00000000¿
END ACTIONLISTOFF
END PART

PART “Danish (Standard)” CHECKBOX     ; Standard Danish keyboard ;
VALUENAME “2¿
VALUEON “00000406¿
VALUEOFF “00000000¿
END PART
END POLICY
END CATEGORY

Yes you need to copy the text in notepad and save it as .adm

Please advise where can I find the valuename, valueon and valueoff details for  English (Australia) - US

please find below:

00000409   English (United States)

00000809   English (United Kingdom)

00001009   English (Canadian)

00001409   English (New Zealand)

00000c09   English (Australian)

So therefore - ValueOn will be 00000c09 and Valueoff will be 00000409?

Do I need the following as well? OR just between Class user and End Part?

PART “Danish (Standard)” CHECKBOX     ; Standard Danish keyboard ;
VALUENAME “2¿
VALUEON “00000406¿
VALUEOFF “00000000¿
END PART
END POLICY
END CATEGORY

you need to delet the below in your case.

PART “Danish (Standard)” CHECKBOX     ; Standard Danish keyboard ;
VALUENAME “2¿
VALUEON “00000406¿
VALUEOFF “00000000¿
END PART

So therefore - ValueOn will be 00000c09 and Valueoff will be 00000409    is correct.

Then the following steps as advised by you:
Save the above code as keyboard.adm file into the folder C:Windows\inf on the server

Step 2: Create and link a new GPO (call it something like AU English Keyboard Layout)

Step 3: Edit the Keyboard Layout GPO

Step 4: In the Group Policy Editor Window; under User Configuration, right click Administrative Templates and choose Add Template

Step 5: select the keyboard.adm template and click OK until you are returned to the Group Policy Editor window

Step 6: with Templates still selected on the left hand side, select view from the toolbar, and filtering

Step 7: make sure the bottom 2 tick boxes (only show configured policy settings and only show policy settings that can be fully managed) are un-ticked

Step 8: Browse to the following setting (using the view on the left hand side) User Configuration > Administrative Templates > Custom Settings > Keyboard Layout

Step 9: Enable the policy setting listed on the right hand side (AU English Keyboard Layout)

When the above policy gets applied - will the default input language changes from English (United States) - US to English (Australia) - US

OR am I missing any steps? Please advise.

Yes. all is correct.

Thank you will give it at try tomorrow.