As ISO 45001 does not require one risk assessment method, there are many to choose from. Some people who are used to using the Failure Modes & Effects Analysis (FMEA) in design will use a similar method where they assess the severity, occurrence and detection of a hazard using a scale for each to assess the risk. If you are not familiar with the FMEA, or your hazards are not overly complicated, this method can be very complex.
As risk is defined as the combination of severity and occurrence. I like to use a grid for this; either a 2X2 or a 3X3. On the up and down axis of the grid you plot severity from low to high, and on the horizontal axis you plot occurrence from low to high. On the grid when a hazard is high occurrence and high severity it is in a red area, low severity and low occurrence is in a green area. This makes it easy to look and see which are the worst hazards that should be better controlled.