同 is mostly used to link two nouns, each noun composing of maybe no more than 4 syllables, e.g. 老師同學生.
同埋 can be used to link, inter alia, more than two predicates. There is often a pause before 同埋. For example: 去食韓國菜﹑睇電影﹐同埋參加生日會。
同埋 can be used to link, inter alia, more than two predicates. There is often a pause before 同埋. For example: 去食韓國菜﹑睇電影﹐同埋參加生日會。