Everything sold at thecomfortbikeshop.com is brand new, in the original packaging and covered under its manufacturers warranty. Generally the warranties are for 1 year on all bikes and components.
Some brands have lifetime warranties on the frame and 1 year on the parts.
Please refer to the directions and owners manual sent with your bike for more detailed warranty information.
Most manufacturers require professional assembly to maintain the warranty. Your local bike shop has a certified technician that can finish your assembly for you. Unless otherwise noted the bikes come 90% assembled. Just the handlebars, seat and front tire need to be attached. This shouldn't take more than 15-20 minutes. Most bike shops will perform this service for free.