How to add songs to a playlist when the songs are NOT on the Purchased list

Question

In Itunes there used to be, in the Playlist page, a "playlist" which appeared at the top called All Music. In the more recent versions of Itunes this is no longer the case and All Music has disappeared and the closest you can get is Purchased. Unfortunately the Purchased list misses out all sorts of things which were genuinely added to Itunes.
In the old days I could select any group of songs from the All Music "playlist" and simply drag them into the appropriate playlist. No problem. Obviously I can still do this if all the songs are on Purchased but, if they are not, what do I do.
I know that it is possible to see all the songs by clicking on Songs at the top of the page and I can then select those that I wish to add to a playlist. But there is no way (that I can see) of dragging these to the required playlist since playlists do not appear in this page format. There is nothing in File or Edit which looks useful. I even tried Copying the selection (in desperation i must admit) with a view to subsequently Pasting to the appropriate playlist but, as I expected, that has a greyed out Paste so no luck there.
There obviously must be a way of adding songs which do not appear in Purchased to a playlist. What am i missing?

Answer 1

Hi scroobyplex, I think i am now fairly happy with the situation as explained in my last post but, as you have taken the trouble to reply, i will try to explain myself a bit better as i don't seem to have been very successful so far.
As I mentioned in my 2nd post, I am well aware of the Categories button at the top left of the screen under File/Edit/View etc. For me this is always set to Music since i don't use any of the other categories.
I am not sure what you mean when you say clicking on Music shows all my music files. In fact, when I click on category Music, I then get various choices appearing along the top of the screen as mentioned in my 1st post - Songs, Artists, Albums, genres, Playlists. If i choose any of the first four I do get a full list of all my tracks but there is no facility there for dragging selected tracks onto a specific playlist.
The other option is Playlists. This gives me a list of all my current playlists,both those created by me and those created automatically by Itunes (of which the previously mentioned  Restored Playlist .... playlist is an example) The Playlist screen always opens with one of the playlists already selected
The only option i have then of seeing a different list of tracks is to select a different playlist. If i want to add new tracks to a playlist, often the Purchased list will be OK as a source for dragging but, if i have loaded a CD into Itunes, I would need to select the Restored Playlist... playlist as any new tracks seem to automatically go onto this regardless of the source. There is nothing else which gives me a full list of tracks on a screen which permits dragging onto any specific playlist.
As mentioned in my previous post I have no idea why all my music, both old and new, goes into a playlist called  Restored Playlists....  instead of something sensible like Music or All Music but it does what i need so i no longer have a problem