Well likely before I made the purchase I'd of already done a bunch of research. So I should have some familiarity with it. Even if it's something I'm decently familiar with though, I'll always read the start up guide and generally follow that.
If there is a separate manual from the start up guide, I won't read the whole manual. Because unless it's something I'm very accustomed to, I need to have some sort of reference when I'm reading/analyzing the information. Otherwise I won't really be able to retain the information
So basically it would go like:
1. Find product I'm interested in.
2. Research said product. Look at reviews, ask people, price shop, etc.
3. After purchase open it up and look at the start up guide(assuming there is one). Read step 1, execute. Read step 2, execute. etc. Obviously if some of the steps are extremely simple like opening the box or whatever, I can move on to other steps.
4. After everything is setup, assuming there's some sort of customization or user interface afterwards, I will likely mess around with it for 15 minutes or so then use the manual as a reference tool. I just want to get it to operate smoothly before I learn every inch of detail about said product.