THis will allow you to " open the chain " and remove links
PARK TOOLS CHAIN BREAKER
As for the fork you ideally should put as much of the headset onto the fork then cut the end, where you cut will be rough and uneven and will be difficult to get the headset on afterwards, hacksaw is fine just cut it longer than you think and add a spacer or two rather than cut it too short and completely mess the fork up.
SCOTT !
To adjust the chain you will need a chain breaker
THis will allow you to " open the chain " and remove links
PARK TOOLS CHAIN BREAKER
As for the fork you ideally should put as much of the headset onto the fork then cut the end, where you cut will be rough and uneven and will be difficult to get the headset on afterwards, hacksaw is fine just cut it longer than you think and add a spacer or two rather than cut it too short and completely mess the fork up.