Zigbee Frame Control Sequence, CC2520
I think your question shows a bit of a lack of understanding, but I'll try and provide a few pointers at least.

You should read the ZigBee protocol standards for starters if you want to understand ZigBee.

You may also be mixing up "FCS Frame Control Sequence" - the FCS in your link is the Frame Check Sequence - it's an error check (ie CRC). The Frame Control is a bitfield containing information about the frame contents.

The ZigBee protocol is a layered protocol. The MAC layer that you refer to is actually part of the IEEE 802.15.4 protocol rather than ZigBee, and is not normally something the user has direct control over when communicating with a ZigBee Dongle (including the TI stack, although I don't know the 2520 specifically but I assume it runs the standard TI ZStack).

If you are using TI chipset, then you should read the ZStack documentation from TI as this will control the MAC layer (and others) - you will not need to worry about this.