3 ways. 1. Already know enough to glance at some spec sheets and build the rest in your head. Aka, lots of experince. 2. Execute a known good build configura

3 ways. 1. Already know enough to glance at some spec sheets and build the rest in your head. Aka, lots of experince. 2. Execute a known good build configuration. 3. Combo of the 1st and 2nd points to suit your ability. Ask people with more knowledge for guidance. Maybe rebuild it once or twice.