PSP 2018: How do I apply tags while previewing pics?

[Telorast]

New to PSP: I created tags and want to apply ratings & tags at the same time when I preview new pics. You can type in tags in Manage tab, but it seems ridiculous if you've already created a list of tags which could easily show as a pop-up list. Tags don't autofill after typing the first few letters in Manage tab. It would be easy to end up with several duplicates if you enter a "cat" tag and later forget & enter "cats", which would make a 2nd tag. The Help files show how to apply tags to Collections, which would have its uses, but would be inconvenient for initial sorting of pics. How is it done?

Edit... just looked at title of this post & realize I must be making a really dumb mistake! Plz have pity on the noob. I really did look in Help files!