Currently, the only way to mine on Astor testnet is using our Python CPU miner. You can follow the tutorial here to start CPU mining.
The SHA3 algorithm was specfically designed by the Keccak team to be particularly efficient in hardware implementations. If you are interested in building a miner we suggest you use these resources:
If you would like to start immediately mining SHA3 for monetary gain, consider researching the 0xBitcoin project as a proving ground for mining hardware: