Can somebody tell me what my strength modifier is? I cba to check the character sheet. And can you provide the link to that dice roller thing? I don't wanna have to go look through the previous pages to find the link.
Attack Roll is usually a d20 (20-sided dice) for characters. It'll be specified on your sheet.
The DM will tell you if your attack score is above the targeted defense (which is also specified as a "versus" on the sheet) of the target character, and that will count as a hit which he will tell you to roll damage for. The party usually isn't privy to the actual defenses of their opponent, but eventually after enough hits and misses an educated guess can be made.
The dice used in a Damage Roll is different from character to character, and can range anywhere from d4s to d12s. You'll have to look it up specific to your character anyway.