The fact that your wife is staying home with the baby is going to make everything really much easier and doable. There is no need to change roles or slow down per se.
Babies just want to sleep, poop and cry for the most part in the first few months. It's around months 8+ that things start getting interesting. Typically, most of the work is going to be done by your wife regardless of how much you want to be involved.
Whatever you can do to help your wife then that's what you should do. So do the extra chores around the house, pick up the grocery shopping. Schedule time for her to go have some "me" time doing something (if she needs it - some mothers will want to be with their baby no matter what). Pay for house cleaning or add another shift to it.
In your case, sleep is going to be important. Expect to wake up 3-4 times a night for a while. If you snore, save your wife the hassle of you and the baby and sleep in the basement or another room some nights of the week. For your own sanity, you may also want to do this.
It might make sense to start bringing work home and do it at night if you want to spend more time at home. You need to be home early evening to provide help and support but it doesn't mean you can't do work after the baby is put to bed.
Also, you'll have a bunch of appointments that you'll need to go to during the day. These are spaced out and are check ups.
Overall, if you are a workaholic and work at all hours, that's going to have to change because the baby will dictate your schedule to some degree. In terms of spending time with the baby it becomes more relevant when they start to crawl and get into the toddler years.
Changing jobs is a bit drastic with one baby and when the wife is going to be home.