How can I find someone online to mentor me on my first research paper?

Answering your questions with suitable answers for doing research you must have the following:-

1. A topic or brief subject on which you want to work. In CS field, start find faults and raising questions to yourself about the topic you learn, e.g. while learning sorting in Data structure, what other technique you can suggest while simplifying existing techniques, etc.
2. After the topic is decided, find who had done what work on your topic. It means to find references to your research work, because without references you cannot write research paper. e.g. search websites of IEEE or research gate.
3. Read any book on research methodology otherwise you will remain just a blogger. hahaha
4. Al last but not the least, find a research guide online or offline.

For any other queries, you can post me again

I would suggest taking to professors at your institution. If the semester is in session, you can go to their office hours; otherwise, you can email your advisor or another professor who knows you. Even if it's outside their area, they should be able to steer you in the right direction.

Depending on how serious you are (and what you mean by the word "research") your best bet may well be to search out professors in that area of research, no matter where they are in the world. You could simply explain your position to them, and ask for they would be willing to work with you on the paper.

You may well get some "yes" answers. This could also be a good way to start a relationship that could lead to a doctorate.

Good luck!