Is ForkDelta same as EtherDelta?
No, ForkDelta, as its name somewhat suggests, began as a fork of EtherDelta.
Taking this off of the site,
This interface is a fork of EtherDelta with a ton of improvements including a much faster order processing system. It interacts with ForkDelta's revamped API and EtherDelta's original contract.
ForkDelta forked about five months ago or so, and although the sites are similar, ForkDelta claims to offer improvements over Etherdelta, though I would suggest actually visiting the sites to see which one is better for you.
As for additional help on how to use ForkDelta, the site shows some very basic instructions that are essentially ‘deposit coins and go’ . You can see this by navigating to ‘My Transactions’ and then ‘Important’.