I have already funded the giveaway by sending 2.5 BCH to bitcoincash:pzq2vg8ppftlnk7raj452eae33upjgedj5dnc5efg5.
This is no ordinary address, this is a P2SH address, which means that it is a "smart contract" address. Anyone who wants to spend from it must satisfy the contract, and I designed it so that ANYONE will be able to satisfy it. First come, first served! :)
There's a catch, though - the contract uses Script features (native introspection opcodes and OP_MUL) that will only become available when the May 2022 Bitcoin Cash upgrade will be activated. Because of that, nobody can spend from the address yet and that gives you a few days of time to figure out how to craft the spending transaction in anticipation of the upgrade activation.
Anyone is able to do the same, so it will be a race - who will broadcast the valid spending transaction first and at the right time to claim the reward?
The contract redeem script is:
and here's a link to a very useful tool for Script contracts (kudos to @bitjson): https://ide.bitauth.com/.
I suggest using Electron Cash to make a dummy TX that sends to your address, export the TX into a file then edit it in your favorite text editor to replace the input with the one spending the reward, load it back into Electron Cash and broadcast!
The transaction format is documented here: https://reference.cash/protocol/blockchain/transaction/
I will not give any other help - you figure it out, good luck!