click on Edit tab → New → choose Part of speech → type Synonym(s) → click Save
Part of speech
Decide which literals a synset consists of and what part of speech all of them belong to: noun (n), verb (v), adjective (a) or adverb (b).
Type down the respective literal (one or more - click on Add button to add more synonyms), specify word and sense number.
||literal always has to be numbered, i.e. you have to provide a sense number for it
|distinguish different senses
||e.g. bank:1 - financial institution, bank:2 as in "river bank"
|lower numbers = basic senses
||it is usual, as you can observe in Princeton WordNet (2.0 and higher), to assign lower numbers (1, 2, 3) to the basic senses
|number of meanings
||senses in PWN 2.0 are quite often too fine-grained - see e.g. verb to get (36 senses); we recommend to translate only the senses that can be confirmed in a corpus
Except of Part of speech and Synonyms (which are necessary), you can add other information as well. For example definition, usage, relations (to other synsets; e.g. hypernyms), ...