Can help me create a website login tool?

I'm currently creating a bot attempt, since I don't know much and I'm just learning haha ...
I would like to add an interface to connect to the website and request a code that the site returns in its url,
but I have really read some things about WinHttp but I have not understood anything or I have not managed to work as basic as I have found

Using live http, I have taken the following .. first an image

[Only registered and activated users can see links. Click Here To Register...]

sorry for crossing out the site, if necessary I will place it

Example Url

Code:

https://api.test.com/dialog/oauth?response_type=code&client_id=0ad0734dc5df644018b5fbfc8265ec6c05bb218dc&state=xyz&lang=es&Scope=scope_general%2Cscope_billing&fbclid=IwAR09eHfj34Dd128WnaGCN1I1aOwe7Yk8ZpCIEITBldBO_nprm4bH48qkCkU

In the first box have

Code:

Origin: https://api.test.com
Upgrade-Insecure-Requests: 1
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36 OPR/64.0.3417.92
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Sec-Fetch-Site: same-origin

And Second

Code:

edit[destination]=https://api.test.com/dialog/oauth/authorize?billing_id=1063&game_id=gflat&name=G+F&redirect_uri=https%3A%2F%2Fwww.test.com%2Fcontent_only_launcher&scope=scope_general%2Cscope_billing&client_id=0ad0734dc5df644018b5fbfc8265ec6c05bb218dc&response_type=code&state=xyz&scope_granted=&edit[form_id]=account_login&edit[id]=MyUser&edit[method]=oauth2&edit[pass]=MyPass&op=Iniciar sesi�n

Changing in the second box Where says MyUser,MyPass when pressing send me connects to the site, but with the scripts he found, nothing can be done, nor edit or how to add all this, if you can help me and explain I would like Please!