Yes, you can mine DHX without having an M2 Pro miner.
However, having an M2 Pro miner will help to cut your MXC costs in half since you still need to lock some MXC and bond some DHX.
To mine DHX, you first need to generate your mining power (mPower). To generate the mPower, you need to lock some MXC token for a certain period of time. The longer you lock the MXC, the more your mPower will be boosted. Once the mining power is generated, you need to deposit and bond some DHX token. You can buy DHX token from an exchange.