Complex lifestyle and leads us to get on the correct path

Today, we are living in very complex world. Various lifestyles inspire us greatly. So as being a modern layperson, it is difficult to know good karma and bad one. How would I will be on good path and eventually attain Nirvana with 21 century lifestyle? I wouldn't know which activities and deeds have to stop from doing. Which Buddha teachings do I have to follow, differentiating current lifestyles and livings?