I'm trying to understand the Mifare EEPROM memory structure. I found out this guide which was quite helpful. In below it covers the Memory block structure:
1K Cards - 16 sectors of 4 blocks each (sectors 0..15)
4K Cards - 32 sectors of 4 blocks each (sectors 0..31) and 8 sectors of 16 blocks each (sectors 32..39)
It covers only the classic series and I'm not sure if it is identical for the Desfire series Memory block structure.
Also, I want to use Desfire 8K cards and don't know how many 4blocks and 16blocks sectors it has. I tried to read the official datasheet but I couldn't understand this part.
The Mifare Desfire series of products don't have any block structure you can access, they are type 4 NFC cards.
Type 4 cards use Command application protocol data unit (C-APDU) and a file type structure to save data.
See the NFC Type 4 spec at http://apps4android.org/nfc-specifications/NFCForum-TS-Type-4-Tag_2.0.pdf and the Datasheet for a Desfire (EV3) card https://www.nxp.com/docs/en/data-sheet/MF3DHx3_SDS.pdf
That guide is specific to the Mifare Classic series of Cards