Real World Flight Schedules vs ASM Schedules

Hello, I am new to Airline Sim and am trying to understand how flight schedules work taking this particular example of Indigo flight 6E651 from BOM to DEL (image captured from flightradar24). This flight departs daily at the same time but I noticed that the aircraft type is different everyday. (And this is similar with any other flight). But when I plan a similar schedule in ASM, everyday the same aircraft (VT-ALV) flies on this route as shown in the 2nd image.

Am I planning my flights incorrectly or is there a flight scheduling method that I am not aware about.

Thanks.

You can schedule with 7 different planes but you don’t have to. Real world airlines will change as per there needs which is not possible in AS.
There is no difference between 1 plane or different planes in terms of demand.

Thank you for the clarification. Are there are resources or topics on ASM where I can learn more about scheduling flights, wave patterns and connection times (other than the handbook)

Search youtube for available tutorials. There are some very good ones (from Pinto for example). And search the forum for “guide for beginners” from yukawa: AS for beginners - an attempted blog