Hey brother, I am not certain on this one. I've always only had expereince with the powdered HCG that needs to be mixed in order to use. I know that there is ome available out there on the maket today that is different and it comes pre-mixed in a stable solution. For this question, I am going to suggest that you reach out and talk to Naps. You can reach his customer service here : https://www.napshelp.com/ When you send your message, be sure to let them know exactly which product you purchased and Im certain that they will help you out.
As for when to start, it all depends on how much you have, but I would time it up so that you can take 250iu 2x wk right up to PCT
As for IM vs Sub Q injects, HCG can be injected either way, but IM is perfectly fine. In fact, it may give slightly higher blood levels vs using it this way