If I use tera on steam how can I log into the game without steam?

lol What are the odds you'd ask about the same thing I told someone just yesterday that it's not a commonly asked thing!

Here's the post I was referring to:
Is there any way to play Tera with a Non-Steam Account? (9th June 2017)

As explained in step 2, you can skip step 4 if you use up-to-date launcher files. Here's a latest copy I uploaded for him:
TERA - Steam to normal launcher files - 01.12.2017.rar
44 MB instead of 42 GB sounds good.