First time job always asking what to do

I'm currently working in an office doing accounting, and it's my first job. Every time I get assign work from my boss and finish it, I always ask what's to do next but I feel weird doing so like I'm bothering them. Also, sometimes my boss isn't in the office and I finish my work but, there is another employee who works there for quite some time so I always ask him but he doesn't seem to know what my boss wants me to do? So usually does every one need to ask what there is left to do after they've done everything?

Yes, it's actually good and proper to ask. I feel the same way as you. I don't want to interrupt my boss or disrupt their flow but they want me to ask anyway.

I agree! It is better to ask because if you just sit there, confused on what to do next, your boss might become upset or something, you know? So even it you do end up annoying your boss, you will then know for sure what you do next. If your boss does become annoyed, they'll get over it when they realize they you are being a good employee by doing this. So, even if you are nervous, just do it and ask!