I think it's easy to feel a lot of pressure at the beginning to know everything and to be productive right from the start. Hopefully this isn't necessary. Everyone will expect you to need to be familiarize yourself with the tools and the code base. They aren't paying you until September, and they know that.<p>Unless this is a short-time consulting gig, they haven't hired you for what you can do in the first month, but what you can do over the course of a year or two. It's okay to learn on the job; it may seem like a lot of time to you when you first start, but in the context of recruiting, your yearly salary and benefits, providing your office, etc, the time you spend learning in the first few weeks is nothing.<p>I think the most important thing is to be relaxed and have your non-work affairs in order as best as possible. You don't want to be distracted by stuff at home while you at work, if possible. If you are like me, you will also find it very hard to turn your brain off when you go home at the end of the day for the first month or two, and it's important to have things going that are interesting and relaxing (hiking, movies, craft, trivia night, whatever). And whatever those things are for you, do them a lot now while you have the time!!