Not a dumb question; we have all been beginners. Although I gather you'll be given some personal tuition by experts, here's a quick summary for the benefit of others who may be wondering.
Near the top of the Forum page is a blue clicky for starting a new thread; you used it to start this one. The page that opens so you can start the new thread includes, just under the "title" window, an option to use one of the common prefixes (Prefices?) such as Tech, BS, etc.
Now for the clipboard. Most computer software used by consumers uses a "Copy" command in which a section of text (for example) is highlighted by moving the cursor, selecting "Copy" from a popdown menu (usually headed "Edit"), moving the cursor to where you want the copied text insertted, and selecting "Paste" from the same popdown menu.
The text that was 'Copied' is kept in the Clipboard, a flexible section of short term memory in the computer and (unless it is huge) it stays there until the next time you use the "Copy" command.* That's why the suggestion was made about copying text from your first PM and then just pasting it into successive, subsequent, PMs. It also allows you to transfer text from one application (Word, say) to others such as Excel, Powerpoint, emails, web browsers (and thus Mudcat) etc.
* If you use "Cut" from the Edit popdown, the highlighted text will disappear from your source document but it will be kept in the Clipboard and thus you'll be able to use "Paste" to insert it into other applications as above.
Small amounts in the Clipboard may be kept even if the computer is shut down (although you should practise with nonessential items on yours to check) but if the Clipboard contents are large, most applications will ask, as soon as you attempt to shut the application down, whether you want the Clipboard contents saved.