Is an AE Card is different from Octupus Card? Can Octupus card can be use to AE to Tsing Yi station?

Yes, they are different. You can use the Standard Octopus Card and purchase the AE tickets. Don't worry.

thanku! but is it ok if we buy the Octupus Card only? that we can use it on AE and the same time in other MTR lines? what if we will arrive HK in the 11th & we will depart on the 14th? what Octupus card we should buy? Tnku!

You can use it on AE and the next metro ride will be free. If you will arrive on 11th and depart on 14th, then you are advised to purchase a HKIA AE Travel Pass which contains a single or two AE journeys with unlimited metro rides in three days. The single AE travel pass will charge HK$250/person, while the double AE travel pass will cost HK$350/person.