You have a few options.
1. several batteries: This means you have to monitor several batteries, but the current draw is split up amoungst several batteries.
2. use 1 battery big enough: Thgis means you have to monitor 1 battery but it has to be capabile of suppying enough amps to run how ever motor r running at once.
I personally tend to use 1 battery that is capable of suppling the needs of the whole project as this is my preference.
I usually use a battery that is over spec for capacity and max amps as I find manufactures lie big time about the capabilities of their batteries and also batteries perform poorly when used at close to their max current draw.
The wires you posted look like what you will need to be able to connect to the batteries and you will need to also buy some dupont jumper wires for the H-bridge connection.
Do be very aware that there isn't a standard way that these batteries r wired up to the plug and can be wired either way. Check the polarity before connecting to anything. I have had projects running fine then the battery went flat so I changed it to another battery from another supplier and connected then the project smoked up because the new battery was wired the opposite way.
Also FYI if you connected 1 of those batteries you posted to the 5v rail (without connecting anyother power supply) on the RPi it will probably run the RPi. Although the RPi normally takes 5v it is in fact a 3.3v system and has an on board DC to DC buck converter to regulate the voltage down to 3.3v, so it is likely the 3.8v connected to the 5v rail will be regulated down to 3.3v to run the RPi fine but no promises