Page custom Page1Create Page1Leave PAGE_CUSTOM_FIRST
Page custom Page2Create Page2Leave  PAGE_CUSTOM_SECOND
Page custom pgPageCreate pgPageLeave PAGE_CUSTOM_THIRD

Function Page1Create  
  nsDialogs::Create ${MYPAGE_FIRST}  
  Pop $Dialog1
  ${If} $Dialog1 == error
      Abort
  ${EndIf}  
  ${NSD_CreateLabel} 0 0 100% 12u "${WelcomeTitleText}"

    ${NSD_CreateLabel} 0 13u 100% 42u "${WelcomeText}"

  ${NSD_CreateRadioButton} 5% 100u 100% 12u "${InstallSAEText}"
  Pop $InstallSAE
  ; default checked install SAE
  ${NSD_Check} $InstallSAE

  ${NSD_CreateRadioButton} 5% 120u 100% 12u "${SkipInstallSAEText}"
  Pop $SkipInstallSAE
  ${NSD_Uncheck} $SkipInstallSAE
  nsDialogs::Show
FunctionEnd  
  
Function Page1Leave  
  MessageBox MB_OK "Page1 leave"  
  ${NSD_GetState} $InstallSAE $1
  ${NSD_GetState} $SkipInstallSAE $2
  MessageBox MB_OK "$1, $2"  
  ${If} $1 == ${BST_CHECKED}
      Call Page2Create 
  ${ElseIf} $2 == ${BST_CHECKED}
      Call pgPageCreate
  ${EndIf}
FunctionEnd 


Function Page2Create  
  MessageBox MB_OK "Create Page2"  
  nsDialogs::Create ${MYPAGE_SECOND}  
  Pop $Dialog2
  MessageBox MB_OK "$Dialog2"   
  ${If} $Dialog2 == error
      Abort
  ${EndIf}
  ${NSD_CreateLabel} 0 0 100% 12u "This is second page"
  MessageBox MB_OK "Page2 show"  
  nsDialogs::Show  
FunctionEnd  
  
Function Page2Leave  
  MessageBox MB_OK "Page2 leave"  
FunctionEnd 

I hope create mutil dialog for my app install process