You only need two things to calculate Young's Modulus - stress and strain.
YM (Pa) = Stress (Pa) / Strain (no unit)
However you may not be given these directly in a question - if so you need to know
Stress (Pa) = Force (N) / Area(m^{2})
Strain (no unit) = Extension (m) / Original length (m)
You may not be given any values at all to calculate YM - you might need to use a stress/strain graph. In this case YM is the gradient of the linear region at the start of the graph.
Take care with units when calculating YM - there are often unit prefixes (e.g. MPa or GPa), and you must take care when calculating area from diameter if unit conversions are involved.
Also strain should be entered as a decimal rather than a percentage - if the strain is quoted as 10% it should be entered as 0.1.