Help! I hope I can post this here

I have my sister's wedding next month I have no idea about what to wear to her wedding. I never cared abt outfits. I attended marriages when I was a small boy. After that, I never attended a wedding and I don't know what to wear. Now I'm 25. Somebody give me fashion advice regarding this. Somebody tell me what to wear for reception and wedding ceremony. Indha sub la kekuranu yaarum kova padathinga, naan vera sub thedi paathan but dedicated ah edhuvum kedaikala Thank you