Custom Select fields can be added by clicking on the + button in the Global or Local Fields manager, and by selecting the field "Select".
Planners can edit the internal name of the field (e.g. Accommodation), the label which is what your Participants will see (e.g. Accommodation need), and the category the field belongs to (e.g. Travel information).
You can then add Values to be selected from - Only one value can be selected by the participants.
You may also translate each value: Select the value, and type its translation in the relevant language field.