There are two versions of each size of sensor array, an analog and a digital version. The digital version will just tell you if it sees a reflection or does, while the analog one will give you the strength of the reflection.
If you want to use the analog version, you can connect it to the analog input pins - there are four at the bottom right of the roboRIO, and 4 more on the MXP. A description of the pins on the roboRIO can be found in the roboRIO User Manual. You’ll need to connect each individual reflectance sensor to a different pin.
If you want to use the digital version, you can connect it to the DIO pins; there are ten on the left side of the roboRIO and ten more shared with SPI and PWM on the MXP. Alternatively, you could use an IO expansion breakout like the SparkFun SX1509 and read the values through I2C. Using this board could simplify your wiring significantly.