Implementing High Pass Filter in Simulink
Those blocks are fine to use.

You vary the cutoff frequency via the TimeCostant input block. 

Please note the cutoff is in \$\omega\$ so for 50Hz cutoff you will need to enter in the period of \$\frac{1}{2*\pi*50}\$

Try the "Plot Freq Response" checkbox to check the step-response &amp; view the bode plot for a particular filter setting



A similar process exists for the 2nd order filters, but with the additional damping factor