Why does my batch file generated text not format properly? - file

Question

The Problem:
I'm trying to create a batch file which randomly generates passwords, but I cannot seem to get the generated passwords to format properly.
Before, I just chose to generate numbers, but I realized that it wasn't very secure for users, and I needed to include letters and numbers. I attempted, but it output the wrong thing (kind of).
I want the generated passwords to be at least 8 characters long, and 32 characters maximum. I tried it, but it completely broke the code and it wouldn't output anything at all. Also, it outputs the same passwords for each one on every option. For example, if I chose option 1 (generate 2 passwords), it would output ud8aqas and ud8aqas. If I chose option 2 (generate 5 passwords), it would output p9dkda, p9dkda, p9dkda, p9dkda, and p9dkda, and so on.
The code that I want to use:
#echo off
:Start2
cls
goto Start
:Start
title DotPass Password Generator [BETA]
echo Thanks for using DotPass! If you have any questions, feel free to email us at mhartmix#gmail.com.
echo Please maximise this program so you can see all of the details we have shown!
echo ------------------------------------------------------------------------------------------------------
echo DotPass will generate you a new PIN (or password, if that's what you're going to use it for).
echo You can use these for any of your online accounts! Remember to always note the PIN/password down somewhere!
echo -------------------------------------------------------------------------------------------------------
echo Note: The passwords/PIN's can only be seen by you, not us. To read more, go to github.com/TechGeekMic/DotPass/blob/Main/security.md
echo Passwords generated are never stored on the cloud, or locally, so that's why you should make a note of your randomly generated PIN/password.
echo -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
echo How many passwords do you want DotPass to generate?
echo 1) 2 Generated Random Password
echo 2) 5 Generated Random Passwords
echo 3) 10 Generated Random Passwords
echo Type the number of your choice below. ( i.e 2 )
set input=
set /p input= Choice:
if %input%==1 goto A if NOT goto Start2
if %input%==2 goto B if NOT goto Start2
if %input%==3 goto C if NOT goto Start2
:A
cls
Setlocal EnableDelayedExpansion
Set _RNDLength=12
Set _Alphanumeric=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Set _Str=%_Alphanumeric%987654321
:_LenLoop
IF NOT "%_Str:~18%"=="" SET _Str=%_Str:~9%& SET /A _Len+=9& GOTO :_LenLoop
SET _tmp=%_Str:~9,1%
SET /A _Len=_Len+_tmp
Set _count=0
SET _RndAlphaNum=
:_loop
Set /a _count+=1
SET _RND=%Random%
Set /A _RND=_RND%%%_Len%
SET _RndAlphaNum=!_RndAlphaNum!!_Alphanumeric:~%_RND%,1!
If !_count! lss %_RNDLength% goto _loop
echo Your two randomly generated passwords are !_RndAlphaNum! and !_RndAlphaNum!
)
echo What do you want do to? Here are a few options.
echo 1) Go back to the beginning
echo 2) Exit DotPass
echo 3) Shutdown your computer
echo Type the number of your choice below. ( i.e 1 )
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2
if %input%==3 goto Shutdown if NOT goto Start 2
:Shutdown
shutdown
:Exit
exit
:B
cls
Setlocal EnableDelayedExpansion
Set _RNDLength=12
Set _Alphanumeric=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Set _Str=%_Alphanumeric%987654321
:_LenLoop
IF NOT "%_Str:~18%"=="" SET _Str=%_Str:~9%& SET /A _Len+=9& GOTO :_LenLoop
SET _tmp=%_Str:~9,1%
SET /A _Len=_Len+_tmp
Set _count=0
SET _RndAlphaNum=
:_loop
Set /a _count+=1
SET _RND=%Random%
Set /A _RND=_RND%%%_Len%
SET _RndAlphaNum=!_RndAlphaNum!!_Alphanumeric:~%_RND%,1!
If !_count! lss %_RNDLength% goto _loop
echo Your five randomly generated passwords for you are !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum! and !_RndAlphaNum!
)
echo What do you want do to? Here are a few options.
echo 1) Go back to the beginning and start again
echo 2) Exit DotPass
echo Type the number of your choice below. ( i.e 1 )
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2
if %input%==3 goto Shutdown if NOT goto Start 2
:C
cls
Setlocal EnableDelayedExpansion
Set _RNDLength=12
Set _Alphanumeric=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Set _Str=%_Alphanumeric%987654321
:_LenLoop
IF NOT "%_Str:~18%"=="" SET _Str=%_Str:~9%& SET /A _Len+=9& GOTO :_LenLoop
SET _tmp=%_Str:~9,1%
SET /A _Len=_Len+_tmp
Set _count=0
SET _RndAlphaNum=
:_loop
Set /a _count+=1
SET _RND=%Random%
Set /A _RND=_RND%%%_Len%
SET _RndAlphaNum=!_RndAlphaNum!!_Alphanumeric:~%_RND%,1!
If !_count! lss %_RNDLength% goto _loop
echo Your ten randomly generated passwords for you are !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum!, !_RndAlphaNum! and !_RndAlphaNum!
echo What do you want do to? Here are a few options.
echo 1) Start again
echo 2) Exit DotPass
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2
if %input%==3 goto Shutdown if NOT goto Start 2
You can try it out for yourself as long as you don't publish it or modify it.
I am very new to batch scripts! Can someone help?