Write a script to automate actions on the site

We need a web programmer. You need to write a script for the site.
It is necessary:
- Authorization on the site
At the right time, the program (script) clicked on the desired button
- further in the window that appears, pressing the desired button
- logging out
- Authorization under a new user

I tell the details to interested and willing to try their hand
What to write is not important, the main result of the program