Hello Alan! Welcome to CC. As stated above User2User is a great place for techy questions and "how do I" questions/answers, a lot are already there but if you don't find what you need feel free to post away.
When you find a thread you want to comment on, jump right in! If you want to reply to a certain remark then hit the Reply button on the bottom of their post.
If you want to start a new thread, go to the forum you want to post in and type in the title as you did for this one. You may have noticed that it took time for this post to be displayed "pending approval" ALL NEW POST GO THROUGH THIS so do not fret if you start something new and do not see it right away.
Lets see..... trying to remember what else I found helpful to learn when I started.......
OH!! If you are in the middle of typing and have to stop, you can save it! Click the little disk on the top bar of your remark box, when you hover over it says "drafts" you can click save or delete.
Oh Private conversations can only be started by paying (donating) members but if you recieve one you can read and reply to it.
Click on a users name/image and you can go to their profile page, depending on how they have it set up some people allow users to post comments there.
If you need other help feel free to ask, LOTS of friendly helpful folks round here!
Look forward to seeing you around,
Blessings!