Sentence:  The upshot of the evening was that I got the address of Pendleton 's studio - or rather , of the studio in which he gave his classes , for he did n't work there himself - and <WSD>joined</WSD> the life class , which met every Tuesday and Thursday from ten to twelve in the morning . 
Meaning of the word marked with <WSD> tags:  become part of; become a member of a group or organization