There are no such things that you can earn safely without any risks. So participating in pools or staking in inhere a risk that you should be aware of whether it is on the DEX side or the token you are staked/farmed.
I am confused between farms and pools and don't understand how the calculation works.
If you are still couldn't comprehend both of it, I suggest you better to learn more about all of them first rather than focusing to achieve a massive amount of APR. There are various explanation on the Pancakeswap documentation page that is worth to read if you want to dig deeper about so you should take a look into it since it contains the pools and farms explanation, so does with of how to calculate an APR on pools.
Click for the link.