There are lines of work where employees are paid by the hours they put into their work effort. Of the top of my head, it can be guards for instance or people marketing goods within supermarket alleys etc. It depends on the best practices within your country, within your line of business. 

However, the thing with hourly wages is that although they’re measured by hours, they’re still calculated and paid out either weekly or monthly. I have yet to hear someone getting paid once a quarter (that’s not due to financial difficulties).

So how do you come about measuring someone’s salary by the hours? It’s important to first off measure the normal working hours within a month, within a week. Your local regulation may prohibit working in excess of those hours or limit the excess hours worked so it’s important to monitor those hours against the hours people have worked to make sure you’re not facing fines or worse.

If you’ve got that covered, it’s all about coming up with a routine to recognize the hours a certain person has working during this specific month, regularly calculate the salary and pay for the work they’ve performed.