Like getting good at anything else, getting good with computers requires practice. You must be willing to learn and be ready to invest some time into practice. The more you do it the better you will become. Once you get good at it, your life will become much easier. We live in a day and age where a lot is run by computers.
The first step is to familiarize yourself with where everything is on the keyboard. Next, where everything is on the computer screen. Try this method. Open a Microsoft word document, type out a few sentences, name and save the document to a specific location on the computer. Close out of the document. Now, navigate to where you saved the document and open the document.
You can also enrol in an online course, or a course provided by an education institution near you. It is best to do this research online but if you cannot, then you can go visit education institutions in person and enquire about what they have available. It is worth asking as some governments provide computer courses to their citizens free of charge.
Really what you want is a lot of exposure to a computer, so attempt to get on a computer as often as possible or even write a practice schedule and keep consistent with it. The more your practice the better you will become. I would recommend you purchase a computer as that way you can use it any time. Otherwise, you can borrow one from a friend or family member. Another option would be to find out where a nearby internet café or library is and go and practice on the computers there.