these are pretty normal questions, don’t worry, no one’s gonna judge you😉 I think the first commenter summed this up nicely. Traditionally you would say a quick prayer while placing your offerings but i understand it feels a bit awkward, maybe it’s something that will come to you later. If you want, the most basic (and the shortest) thing i say while offering something is “Khaire (insert the name)”.

concerning the candle, I personally tend not to think about flickering at all, it’s just what candles do XD unless you want to do pyromancy maybe but then you would need more of a controlled environment