Hello Zino! Don't be ashamed, German is a tough language, one has to have time and patience for it (I had to myself haha) and it's actually very nice that you decided to give it a try!
So have a look at this website (it's the BAMF -- the German federal office for migration). This page gives an overview on the different possibilities for refugees to learn German: http://www.bamf.de/EN/Willkommen/DeutschLernen/deutschlernen-node.html
More specifically, you could search the database for German courses (and check whether it would be possible for you to have a grant or something) in you area here: http://www.bamf.de/EN/Willkommen/DeutschLernen/Integrationskurse/KurstraegerNaehe/kurstraegernaehe-node.html
...you could also call them or write them an email through the contact form
From Monday to Friday
09:00 a.m. to 01:00 p.m.
Telephone: +49 911 943-6390)
and ask whether there are groups in your area who organize free German courses. I'm sure there are (there are for sure in Frankfurt, maybe Dortmund is to small but I think you have good chances of finding something).
Something you might also do is to contact the group "Mannheim sagt Ja" (on Facebook: https://www.facebook.com/groups/masagtja/?fref=ts
). They are a wonderful group based in Mannheim but I'm sure they could give you some tips and contacts for Dortmund as well ;)