To Set Series of a job from the Production Board, place a tick in the box
(see below No.1), now click the Set Job Series button (see below No.2).

A Pop Up will appear on your screen, choose from an existing Series from the Drop down or click the orange + to add a new one (see below No.3).

Note:

To set multiple jobs to a Series place a tick in each of the jobs and select the Set Series button (see below No.5).

The Series can be seen here (see below No.4):