How do I respond to comments posted on the question I asked?

[AC Question]

I asked a question earlier about my S5 and issues with lollipop Someone asked if I had tried clearing the cache, The answer BTW is yes. I did clear it.
But I can't find where to answer that question in question thread

 

[Javier P]

You have to register as a new member. Free and easy

 

[Michael Lange]

Thank You

 

[Javier P]

Welcome to the forums!