Single slit diffraction angle between maxima

Lets say we have a certain wavelength $$\lambda$$ and a known slit width $$d$$, how can I calculate (approximately) the angle $$\theta$$ between the central maxima and the next maxima?

I know that $$d \sin \theta = m \lambda$$ gives the minimum (m=1 is first minimum and so on) and that I can approximate $$\sin \theta \approx \theta$$ but other than that I am quite stuck. How can I proceed from here and approximate the angle $$\theta$$?

I have seen the other thread related to this topic but I did not understand the answer there.