There are multiple places you could be stuck on here: understanding what 0 1 means, understand what spin multiplicity means, or knowing what the correct spin multiplicity is. Where are you stuck?

Thank you for the comment for my begunner question.

I used spin multiplicity of 2 for NO, However, optimization process does not converge as follows, even with psi4.set_options({βMAXITERβ: 1000}) # Default is 100

SCFConvergenceError: Could not converge SCF iterations in 1000 iterations.

STO-3G is a terrible basis set, which is why converging the wave function to the degree wanted by optimize is hard. The optimization works fine in a more reasonable basis set.

You can get the calculation to converge in STO-3G as well with

molecule {
0 2
N 0. 0. 0.
O 0. 0. 1.15
}
set reference uhf
set soscf true
optimize('hf/sto-3g')