First of all, I am brand new to the code industry. I am starting from zero.
I am doing a project that I need to rotate the stepper motor 90 degrees every 40 minutes for a day.
I do not know what kits need to build this. I have only Arduino UNO. I have no idea what kind of stepper motor is required. I have to rotate a clock surface which is not heavy at all.
can someone help me out to do the coding? it would be greatly appreciated.
You need a stepper that's strong enough to move your clock face at the speed you want it to move.
Then you need to find a stepper control board that's suitable for that specific stepper, and a suitable power supply.
As it's a stepper you don't have positional feedback, so upon power on you don't know where you are. The typical solution to this is a microswitch or similar sensor that is triggered at a specific position of the thing you rotate.
Finally there's the programming. Having a stepper move 90° (i.e. a specific number of steps) at a specific interval is quite easy, I'm sure you can do this by simply modifying some of the example code that's included in the IDE.
For the timing you may also want to add an RTC, that gives you more accurate timing overall and you don't lose the time over power outage.