How to use Photoshop glyphs ? You can find it via the window menu and glyphs, a panel will appear.
Select the horizontal type tool from the tools panel and then click on the document, set the font size etc and color and then go to the panel and double click on of the cells and the type will then be added at the current insertion point for the text. You can also the font via the top of the panel to say Arial or Apple Color Emoji and then again double click and add a new design.
Select an existing character and the font in the panel will be set to that and you will see the full range of characters / designs available so if you have a thumbs up emoji selected and it is the Apple color font then you can then say go from the thumbs up to the thumbs down by again double clicking an entry in the panel.
You can increase the size of the cells by using the slider at the bottom of the panel. You can also increase the size (scale up or scale down) of the size of the characters in those cells via the two buttons at the side of the slider at the bottom of the panel.
There is also a last used / previously used along the top of the panel and you can quickly add new designs to the insertion point for the type and it will use the font associated with that character or design. Doesn't work as well when you try and select an existing character (of a different font) and replace that as it still remains in the type's font and so you may find you just get a square block indicating there is no design associated with that cell.
Select a font and you will also see below the font drop down, a category. You don't have to use this but it makes it easy to math symbols, currency etc instead of spending 10 minutes scrolling through all the Photoshop glyphs panel.
Sometimes when you select a character and try to correct a mistake, instead the application will helpfully display some alternates and you have to press the key twice to get rid of it or basically just give up because it pops up all the time. It is one of those odd 'we think you will find this useful features' that I find just gets totally in the way. How to turn it off, go to the preferences (edit menu on the PC) and type section and deselect the check box for the layer alternates option and then it will not appear. Hopefully, ever, ever again.