How do I get a visa/residence permit for an Ausbildung (vocational training)?

With a contract (§ 16a AufenthG): You need a signed Ausbildung contract with a company, usually German at B1 level (there can be an exception if the company confirms your language level is sufficient) and enough income to support yourself. If the training allowance is not enough, a blocked account or a declaration of commitment may be required. The visa is usually issued with the approval of the Federal Employment Agency (Bundesagentur für Arbeit); the company can get advance approval (Vorabzustimmung) to speed things up.

Applying: From Turkey you apply through the German missions or the authorised visa centre. German translations of your diplomas and documents are required; check the current document list on the consulate's website.

Looking for an Ausbildung place (§ 17): If you don't have a contract yet, you can also get a visa to look for an Ausbildung place if you are under a certain age limit, have good German, have a school-leaving certificate that qualifies you for university or Ausbildung in Germany, and have enough money to support yourself. Check the current age and language requirements on the Make it in Germany website.

During the Ausbildung: You can work up to 20 hours a week in a side job independent of your Ausbildung. If you have children, you can also do your Ausbildung part-time.

Afterwards: After completing your Ausbildung you can switch to a permit to work in your profession or ask for extra time to look for a job. An Ausbildung completed in Germany also opens a faster route to a settlement permit.