Automate login and click on site topic and button on site.I would like this software to be developed for Windows.

I need you to develop some software for me. I would like this software to be developed for Windows . I have a site where I login with username,password and 2step verification. This site has pinned and unpinned topics. What I want to do is when I run the program that you will develop for me is to click at the first not pinned topic (open the topic) and then inside that topic click a button at the bottom. It will be great also the program to use for connection latest Firefox user agent and can keep cookies and session to avoid login every time that I run it. Limitations: You cannot login from any other PC than mine to that site for testing but I can provide any information that you may need and we can also use team viewer.