How to power two motor drivers and Raspberry Pi with one LiPo battery?
A lipo puts out 3-4.2ish voltage (per cell) depending on whether its discharged or charged. Your battery pack has 3 cells and usually has a voltage of 11V

A raspberry pi needs 5V. 

The motor controller can take 5-30V and then switches the motor's on and off:


Source: https://www.cytron.io/p-mdd10a

You can hook the motor controller directly to the battery.
You'll need a DC to DC 5V step down converter for the rasberry pi to make sure it get's 5V. I'd imagine that most other stuff would run on 5V. Some things run on 12V, if they do get a 12V DC to DC step up module. 

If have a power supply, make sure the voltage is the same for the power supply as it is for the load (raspi). The second thing to check is to make sure the power supply can source more current than the load can use, otherwise the voltage will drop and you'll have a brownout.