Error while setting up the github version on windows

I want to setup openemr for development. I cloned the github, installed docker for windows, and ran docker-compose up, it started up fine, but going to http://localhost:8300 or https://localhost:9300 just gave me a 500 error. I thought it was a docker issue, so i installed xampp, and tried a local setup, but it still doesn’t work.

I checked the apache error logs and got this:

[Sun May 23 12:17:02.524811 2021] [php:warn] [pid 4632:tid 1916] [client ::1:51591] PHP Warning:  require_once(D:\\dev-harshal\\openemr/vendor/autoload.php): Failed to open stream: No such file or directory in D:\\dev-harshal\\openemr\\setup.php on line 98, referer: http://localhost/
[Sun May 23 12:17:02.524811 2021] [php:error] [pid 4632:tid 1916] [client ::1:51591] PHP Fatal error:  Uncaught Error: Failed opening required 'D:\\dev-harshal\\openemr/vendor/autoload.php' (include_path='D:\\xampp\\php\\PEAR') in D:\\dev-harshal\\openemr\\setup.php:98\nStack trace:\n#0 {main}\n  thrown in D:\\dev-harshal\\openemr\\setup.php on line 98, referer: http://localhost/
[Sun May 23 12:17:05.292082 2021] [php:warn] [pid 4632:tid 1920] [client ::1:51592] PHP Warning:  require_once(D:\\dev-harshal\\openemr/vendor/autoload.php): Failed to open stream: No such file or directory in D:\\dev-harshal\\openemr\\setup.php on line 98
[Sun May 23 12:17:05.292082 2021] [php:error] [pid 4632:tid 1920] [client ::1:51592] PHP Fatal error:  Uncaught Error: Failed opening required 'D:\\dev-harshal\\openemr/vendor/autoload.php' (include_path='D:\\xampp\\php\\PEAR') in D:\\dev-harshal\\openemr\\setup.php:98\nStack trace:\n#0 {main}\n  thrown in D:\\dev-harshal\\openemr\\setup.php on line 98
[Sun May 23 12:17:17.355509 2021] [php:warn] [pid 4632:tid 1920] [client ::1:51593] PHP Warning:  require_once(D:\\dev-harshal\\openemr/vendor/autoload.php): Failed to open stream: No such file or directory in D:\\dev-harshal\\openemr\\setup.php on line 98
[Sun May 23 12:17:17.356501 2021] [php:error] [pid 4632:tid 1920] [client ::1:51593] PHP Fatal error:  Uncaught Error: Failed opening required 'D:\\dev-harshal\\openemr/vendor/autoload.php' (include_path='D:\\xampp\\php\\PEAR') in D:\\dev-harshal\\openemr\\setup.php:98\nStack trace:\n#0 {main}\n  thrown in D:\\dev-harshal\\openemr\\setup.php on line 98
[Sun May 23 12:17:21.711942 2021] [php:warn] [pid 4632:tid 1920] [client ::1:51597] PHP Warning:  require_once(D:\\dev-harshal\\openemr/vendor/autoload.php): Failed to open stream: No such file or directory in D:\\dev-harshal\\openemr\\setup.php on line 98
[Sun May 23 12:17:21.711942 2021] [php:error] [pid 4632:tid 1920] [client ::1:51597] PHP Fatal error:  Uncaught Error: Failed opening required 'D:\\dev-harshal\\openemr/vendor/autoload.php' (include_path='D:\\xampp\\php\\PEAR') in D:\\dev-harshal\\openemr\\setup.php:98\nStack trace:\n#0 {main}\n  thrown in D:\\dev-harshal\\openemr\\setup.php on line 98

I checked the repo on github, there seems to be no vendor directory at all. I checked my local cloned repo, that does have the directory but has no autoload.php file. Whats going on?

Here are the instructions for the DOCKER. What steps did you follow? Can you list them here?