Summarize the following:
Let him decide if he wants to have lunch near you, rather than always rushing to eat near him. If he works in another department, don’t spend too much time there or he might feel that you’re being intrusive.  You can send plenty of signals that you’re interested without crossing his boundaries. Remember, no one wants to feel like they’re being sexually harassed at work. If they feel harassed, this could land you in trouble! Some workplaces actually prohibit employees from becoming romantically involved. Others have strict policies about the kind of communication that is allowable while on the clock. Don’t do anything to jeopardize either of your jobs. If it has to wait until after work, let it. Check the employee handbook. If you didn't get a copy, there might be one in the breakroom or office. It could also be available digitally. This can be the hardest part, but it’s almost bound to happen. No matter how subtle you both are, people are sure to notice what’s going on. Workplace gossip helps relieve the boredom of routine, so expect questions and rumors.   Gossip can work in your favor. If your crush wasn’t sure of your intentions, hearing a rumor might help him get the full picture. Decide whether you want to dismiss rumors or be honest about your feelings. This can help you or backfire, so choose wisely. Remember that the things you tell someone in confidence will likely make their way around the office eventually. It’s very common for people to see workplace flirting as a way to get ahead in the company. First, you need to be honest with yourself that this is not what’s going on. Then let anyone who asks know that you would never engage in flirting simply to advance your career. This may not happen every time, but it is more likely if the guy has a higher position than you. With online dating apps, you can easily flirt with (and date) multiple guys at once, and no one has to know. At work, things are quite different. Even if your crush doesn’t realize that you’ve also been flirting with the guy in the mailroom, someone else will. And you can be sure it’ll get back to him.  Seeing or hearing that you were flirting with another guy might make it seem like you aren't that serious or interested. Not all guys get motivated by jealousy or competition. If he sees you with another guy, he may move on, especially if he had feelings for you.

Summary:
Keep it respectful and give him space. Know your company policy. Prepare for gossip. Know that your motives might be questioned. Stick to one guy at a time.