Background: I run 1.14.3 in a separate directory folder from .minecraft
Whenever I try to install Forge for 1.14.3 and choose the directory I use, it comes up with an error saying "The directory is missing a launcher profile. Please run the minecraft launcher first." Even after running the launcher (several times) it doesn't work.
Here is an image of the installer, if it helps. (the folder is called 'aaaaaaaaaa' because i couldn't be bothered to think of a better name. It's just a folder i put everything in when my desktop becomes too cluttered).
Edit: I forgot to mention that i installed it in the default .minecraft folder before, but realised it wouldn't work as the directory for 1.14.3 isn't in .minecraft. Don't know if this helps, just adding it in case.