One question...

Theme: Symbol, component in schematic

How do I get components onto my PCB that have been later added in the schematic?
If you insert new components (symbols) in the schematic after the board has already been laid out , you can drag its package manually onto the board in the lower right corner of the sidebar (drag&drop):

1 (Fig. 1: Packages in the Sidebar)

You can also t
ype the [Ins] key on your keyboard to view the list of missing packages.

And you can also restart the Auto Placer and have the remaining packages placed automatically in one go. You will find the Auto Placer in the layout view in menu "Actions" under "Automatisms and assistants".