First step to build Jeremy is to purchase all the materials. You will need the following

Electronics:

• X1 Adafruit Wave shield (https://www.adafruit.com/product/94)
• X1 Arduino Mega (https://store.arduino.cc/usa/arduino-mega-2560-rev3) (note: any Arduino mega 2560 variant will work fine)
• X1 Flora colour sensor (https://www.adafruit.com/product/1356)
• X2 Ultrasonic sensor (these can be purchased from various different sites) 
• Pololu 70:1 Metal Gearmotor 37Dx54L mm with 64 CPR Encoder (https://www.pololu.com/product/1445)
• 1X Speaker (https://www.adafruit.com/product/1552) (any speaker will work)
• 3X Bump sensors
• 1X Seed Studio Arduino Motor shield (https://www.seeedstudio.com/Motor-Shield-p-913.html)
• 1X 315 Mhz Remote receiver and transmitter (https://www.adafruit.com/product/1096)
• 2X Pololu Aluminum Scooter Wheel Adapter for 6mm Shaft (https://www.pololu.com/product/2674)
• 2X Scooter wheel
• 3X Metal caster wheel (these can be purchased almost anywhere online)

Materials:

• Pine Wood sheet
• Pine Wood planks 
• 4X Wooden dowel
• Wood Glue

The wood type doesn't really matter, but as long as it will be able to withhold the weight of your load (whether that be drinks, plates etc.).