I'm new to Upwork. I'm not sure of how I should calculate my time for scheduling, travel arrangements, and general administrative tasks. As an executive assistant, I am often waiting for instructions from the executive. So, I'm thinking that I should charge based on the hours that I make available to the client. Zirtual, a virtual assistant firm, has VA packages based on a minimum amount of hours. They charge the client for a set amount of hours of work. If the client uses less hours than the agreed-upon hourly package, those hours do not roll over to the next month. However, if the client needs more than the agreed-upon amount, the client has the option of purchasing more hours. I would appreciate any advice. Thank you in advance.