Where am I wrong?

I created this font https://easyupload.io/h7dzvj

but it says it’s raster. How do I convert it?

Hello and welcome to this forum.

In Illustrator, letters must consist of paths. It is not possible to use bitmap images, but you can convert scanned letters into paths:
( A ) Select a letter.
( B ) Call Window > Image Trace.
( C ) Select “Black and White” as the mode.
( D ) Open Advanced.
( E ) Activate the option “Ignore White”.
( F ) Click on “Expand” at the top to convert the letter into paths.
( G ) In Layers, name the letter, here with “A”.
Now repeat steps A - G for each letter.
Then you can drag the letters as paths into the Fontself window and get your font.

Tip: If you scan your font, use 300 dpi as setting, then you will get better results in Illustrator.

My result for your file for testing: YourFont.zip (147.8 KB)