I have replaced the previous pipes with a disposal arm from the disposal and a flanged tailpipe from the 2nd sink to a center outlet continuous waste assembly. Per recommendation from a local hardware store rep, who also said he is a licensed plumber, I did this as a slight drop (hense using the disposal arm pipe) to the assembly. It is then tied directly into the P Trap and inlet pipes coming from wall through the back of the cabinet.
It has not resolved why water still stands in the disposal and in the new pipe. There are no blockages, but water will not drain. What am I doing wrong?

Can you post a picture of the plumbing under the sink. We will take it from there.

Humm a hardwares store clerk who is also a licensed plumber, really? We await the pics and are sure we can help.