My questions are simple guy's;
* where can we find a good mining sites or Apps?
Actual mining requires you miners (ASIC for bitcoin) and/or GPU (for altcoins) depending on what you'll mine. It's not just reliant to the actual websites which you probably have misunderstood as if it's an easy process. But for you to have more idea on what can you mine with GPUs/CPUs, check:
https://whattomine.com/ and
https://www.nicehash.com/* Did it has is own risks different from bitcoin investment?
Yes, you're having your operation run by electricity so that's one risk that the expenses for your electricity might not be par with the coins you mine and based on its current market value.
* what benefit can we stand to gain mining bitcoin or altcoins?
You're helping the network to be more secured. But search on how much an ASIC is for you to have an idea, how much it usually cost for an individual to mine bitcoin.