How to approach and start talking to someone who intrigues me?

Hello,

About two months ago, my relationship broke off after 4 years. She was my first and only until now, which leaves me quite unexperienced when it comes to approaching women. When I started to get a bit over my past relationship, I told myself I wouldn't actively go looking for someone else right away. However, when I see someone who intrigues me, one cannot just let the opportunity go to waste I would say?

Anyway, already a few months ago, when I was still in a relationship, I noticed this girl who works at the same company as me, and who very often takes the same bus to work. I tend to see her almost every day when waiting for the bus to and from the workplace. At first, I just considered it a nice looking girl, but thought nothing more of it. However, now singleness has once again become a part of my life, I started to look at this girl in a slightly different way. Unfortunately, there are plenty of things stopping me from taking any action. So now I just go to work every day, not saying anything to her, but finding myself looking at her a lot of the time. I don't know what it is, but she intrigues me, and I would like to maybe talk to her and get to know her.

What's stopping me however, are several things. First of all, I would have no clue how to open a conversation. This is something I already hardly do with 'normal' strangers, let alone with a girl I fancy. Where does one start?
Secondly, how do I know she's available in the first place? I consider it would turn out quite awkward if I were to find out quickly she is already seeing someone, and can one just ask that on the spot anyway?
Additionally, do I still have a chance at this? I have been sharing the same bus as her for quite a few months now. Do I still have a chance to suddenly start talking to her after all this time?

As mentioned before, I told myself not to go looking for a girl, but something tells me I shouldn't just let an opportunity go to waste when it arises. So does anyone have any sound advice I could take into account? You are most welcome.

Regards

Approach and start talking. Yeah, it's intimidating, but there are a number of well-known small talk subjects that you can start with, especially the weather. And since you are uncomfortable talking to normal strangers, you can practice your small talk on normal strangers.

Then work your way up to talking to semi-attractive women working in retail. Then finally try approaching this girl at work. Only, I think that you should approach her at the bus stop. Start a conversation shortly before the bus arrives, and then sit down next to her so you can continue the conversation.

Is she seeing someone? Two ways I use to find out. One is to do some flirting during the conversation. If she is seeing somebody and/or uncomfortable with your advances, she will eventually mention the boyfriend. A more indirect way is to talk about current movies. If she is interested in you, she will become enthusiastic about some upcoming movie that you are talking about, to hint that you could ask her out.