You have the option of doing:
train 4 days, rest 3 days
or, train 5 days, rest 2 days
Many people find the 5 days, rest 2 days works better for them because they workout in the morning before going to work Monday to Friday and then can spend the weekend doing what they like. This way they also don't have to keep track of which days are workout days and which aren't.
It is up to you as to what would work better with your schedule. Both options will give you results.