Hey to take off the chain you need a "chain tool" which you clip onto the bike chain and twist it and it pushed the peg out of one of the links for you to undo the chain...and to put it back on you do it in reverse - where the peg is pushed out the other side you use the chain tool and twist it to push the pin back in...if that makes any sence...
here is a bicycle chain tool -
http://cgi.ebay.co.uk/NEW-BICYCLE-CHAIN-LINK-T OOL_W0QQitemZ150011042627QQihZ005QQcategoryZ10 9122QQrdZ1QQcmdZViewItem
They are pretty cheap to get.
As for the pedals you need an adjustable spanner and just undo them as you would a normal nut - the nut is properly fixed in/ attached to the pedal so it will unscrew out of the pedal arms and not out of just the pedal...