How to develop a modified buffer block in simulink

I need to create a modified buffer block in order to construct data frames that are 63 symbols long. This block gets "Symbols" & "Delayed Clock" signals as inputs. How can I implement this design in simulink.?

This is referred in one of the matlab webinars. This is the link to it. " https://uk.mathworks.com/videos/implementing-a-wireless-receiver-on-an-fpga-part-2-81925.html " And he's stating this around 17.20 min.