Coupla pointers. My guide was written for the normal Express, not the Urban Express.
Similar, but not the same.
The Urban Express wont need a good back brake cable to start, but a fully charged battery is definatly a good idea. The UExpress uses a 12v system instead of 6, so remember that for charging/replacing.
From there I highly recommend you tear apart the carb, clean it completly and reassemble it. Make sure to turn the adjustment screws all the way in and write down how many turns it took so you can set them back. Then remove them and clean their passages along with everything else.
That should get you started.