I want to write a program like a batch file. Where to start. See below

I access a website frequently throughout the day for my business. I am required to log in, password, enter, scroll down, click a link, type a keyword, drop down menu, click a button, click a button, then I’m where I need to be. How can I write a program that does all this for me please? Thank you very much.

google for “automating browsing” and see what suits you
If you want to communicate with a web server then some python library might be what you want, you might be limited to just being able to print the html of the last page, if you want to resume browsing manually later you might need something that interacts with a browser application instead which sounds like something you’d use autoit for on windows or applescript on mac
There are also browser extensions that might do what you want