Question about a pre-1972 (I think) Datejust

[Iceman332k1]

I was just given a vintage OP Datejust, but I am having trouble getting it working. It does not have a crown that screws down, and as far as I can tell it only has 2 crown positions (1-Date adjust 2-Time adjust). If I remember correctly, it must be wound before the automatic action can kick in and keep it wound, but I honestly have no clue how to wind it. It probably needs servicing, but I would like to get it working before I send it in, if possible.

If more information is required to help answer, just respond and I'll do my best to fill in any blanks.

Thanks in advance!