If it was a few hours ago, use the present perfect. I would not use a comma after "suggested" in either sentence. If it was a few days ago, the simple past would be fine.
Student or Learner
Is it right to say " I have found the movie that your sister suggested , on YouTube." Or
" I found the movie that your sister suggested, on YouTube "
How do I know and be sure which tense to use when I talk about something that has happened a few hours ago or days ago?
I think you could only use the simple past if 'ago' was mentioned, even if it was just a few minutes ago, but I am not a teacher.
"Have found" is more BrE, "found" is common in AmE, in such a context.
To add to what Konungursvia wrote, I believe that's the only significant grammatical difference between British and American English. (Correct me if I'm wrong.)
American's don't apply the British rule about actions in the past, results in the present-- "I found my keys" sounds fine to me as an American. Also, the present perfect sounds more formal and "significant" to us: "I've found it!" sounds like Archimedes speaking.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.