In this context, "ruby" means the standard characters are marked with a phonetic version (a "ruby" version) above it. I think for Chinese, you might see the original text, then a little pinyin or zhuyin version, which is written above. This means the reader can follow the text phonetically. "Consult" means "refer to" or "check". The phrase "consult a dictionary" is quite standard.

A ruby is a red precious stone. I believe the Chinese is 紅寶石. To consult a dictionary is to look something up in a dictionary 查詞典