Assuming your bike is a 700c wheel size, that is the size fork you will need. The steering tube length should be close to the
steering tube length of the fork that is on the bike. Too short and it won't clear the headtube/headset, too long and you
may not have enough thread to tighten the headset down (thread ends before the top of the headtube). The steering
tube length will be specified in the fork description.
Matching the curve is not particularly critical, most carbon forks are straight these days, steel is more likely to be a bit
curved but much less than decades past.