Salesforce - Scheduling a Schedule Job

Following are the different ways to schedule a Schedule Job through a script. Run the given code in Execute Anonymous window and then you could see in Setting -> 'Scheduled Job' that your Job is waiting to be executed.

Run a Schedule Job NOW

Method - 1

ScheduleSalesTargets c = new ScheduleSalesTargets();
c.execute(null);

Method - 2 

(This one I prefer, whenever I need to run a job)

Check the current Time. If it is, let's say 10:39 AM, in your clock, then set the minute to 41. This will schedule the job for 10:41 AM just two minutes from now. But, if you set minute value to 38, then it will schedule to next hour 11:38 AM

ScheduleSales c = new ScheduleSales();
String sch = '0 0 * * * ?';
System.schedule('Sales Job Name - 1',  '0 41 * * * ?', c);

You could repeat following, so that job keeps running every 5 minutes while you debug and change the Apex code behind the scene.

ScheduleSales c = new ScheduleSales();
String sch = '0 0 * * * ?';
System.schedule('Sales Job Name - 1',  '0 40 * * * ?', c);
System.schedule('Sales Job Name - 1',  '0 45 * * * ?', c);
System.schedule('Sales Job Name - 1',  '0 50 * * * ?', c);
System.schedule('Sales Job Name - 1',  '0 55 * * * ?', c);
System.schedule('Sales Job Name - 1',  '0 01 * * * ?', c);

Schedule a Job for every 10 Minutes

global class scheduledTest implements Schedulable{
    global void execute(SchedulableContext SC) {
        RecurringScheduleJob.startJob();
        String day = string.valueOf(system.now().day());
        String month = string.valueOf(system.now().month());
        String hour = string.valueOf(system.now().hour());
        String minute = string.valueOf(system.now().minute() + 10);
        String second = string.valueOf(system.now().second());
        String year = string.valueOf(system.now().year());
     
        String strJobName = 'Job-' + second + '_' + minute + '_' + hour + '_' + day + '_' + month + '_' + year;
        String strSchedule = '0 ' + minute + ' ' + hour + ' ' + day + ' ' + month + ' ?' + ' ' + year;
        System.schedule(strJobName, strSchedule, new scheduledTest());
    }
}