simulation question

you could do it that way

but you can also simply provide stimulus via HDL directly. you generate the input vectors using non-synthesizable constructs like wait statements. for example, you can generate a clock by inverting a signal and waiting period/2 seconds in an infinite loop

using your HDL test bench you can still see what the input stimulus and output response look like in a graphical waveform, generating the stimulus is just code instead of graphical