How to automate actions in the browser?

Question

Automation

It is necessary to automate several actions in the browser
1. Enter text, press the button
2. When "text1" appears on the page, return to the first paragraph
3. When "text2" appears on the page, go to the fourth paragraph
4. Click on the second button
5. When loading the next page, press the button again
6. When "text3" appears on the third page, press the third button
7. If "text3" does not appear on the third page, display the text "You did not have time to buy a phone for the promotion" (optional;-) )
8. Finish script execution
Everything should take no more than two seconds (Internet 10 mb, if necessary faster)