Calculating Forward Rates from Calibrated Zero Curves

Hello,

I am following the example in the blog post here: Strata and multi-curve: Interpolation and risk and want to plot the forward rates as show in Figure 1.

I have been able to build a calibrated zero curve by following the example but can’t see how to generate forwards.

Could you assist please? Have had a look at previous questions and docs but struggling to find this information.

Thanks,
Saad