The sample class supplied with Faximum is called Standard. The deadline for the Standard class is one minute. When this class is in effect, Faximum will send the fax out as soon as possible.
You can override the Standard deadline time by using the Wait to Send feature on the Compose Outgoing Fax window (select Wait to Send on the Options pulldown menu). This feature lets you specify an exact time to send a fax.
However, a more flexible way to schedule your fax would be to create a second class with a longer deadline time and create a tariff that matches the phone rates in effect in your area (or use/modify the sample tariff). Then if you want to send a fax out immediately, use the Standard class. If the fax can wait to take advantage of cheaper phone rates, use the new class.
See Using the Sample Tariff for information on creating a new class with a longer deadline time.