Claiming fork coins are usually done by importing your private key to a software/wallet that supports the fork coin, but there's a lot of information on how you can claim all of it if you will take time to search it on the web.
No, if you can follow simple instructions.
There is a risk because you will have to import the private key of your Bitcoin address to a new software which is very risky especially if you hold huge amount of coins on that address. So better transfer all your coins to a new generated address before starting to import it, also find the official software of the fork coin you are claiming.
Nope, there are no charges for claiming your fork coins.
Majority of those forks coins are useless and worthless since they are just made to make money using the name of the original cryptocurrency that they are copying by proposing a better performance and security by changing the algorithm and increasing the block size but really doesn't solve anything.