They generally come with some instructions - have you got one that has none?
First of all, as its single phase, make sure you get a 240v coil version.
Quick pic below:
The coil is on terminals A1 and A2, and is not polarity important.
There is a hold on contact (usually) hidden behind the green push button, or the green push button actually presses this hidden contact in.
If you want additional start and stop buttons, the green start button is wired in parallel across the current green button, and the red stop buttons are wired in series after the current stop button. You can simply run three cores to a remote start/stop station, as the bottom of the green and top of the red are obviously commoned up.
There will usually also be a set of contacts which close if the overload trips, and these are used to signal to a red 'tripped' light or alarm etc.
You will notice that the third pole of the contactor which would be the htird phase in a three phase setup is being used with a looped neutral - this is considered good practice as the three poles are all monitored for overcurrent.