Under the "build polymer" option you should select the "build unit" and under that you can build the repeat unit of your choice and define the tail and head of the repeat unit. Then follow the standard procedure of building a polymer, only this time you will select "current project" under the library scroll down menu, then select your repeat unit and that should get you going.
Under the "build polymer" option you should select the "build unit" and under that you can build the repeat unit of your choice and define the tail and head of the repeat unit. Then follow the standard procedure of building a polymer, only this time you will select "current project" under the library scroll down menu, then select your repeat unit and that should get you going.