As long as you didn't get a letter from the Finanzamt, telling you to pre-pay income and solidarity tax, you don't do so.
That can either have been: a separate letter that you got after they processed your "Fragebogen zur steuerlichen Erfassung" (you estimated your future income on page 5), i.e. the questionnaire in which you told them you want to become self-employed, and with which you asked for a tax number (= Steuernummer) to mention in all your invoices, or if you have already received a Bescheid (= income tax return certificate that you get after your tax return has been processed), then in your last Bescheid, where it's written in a table.
What you need to look for is a payment schedule telling you how much Einkommensteuer and Solidaritätszuschlag to pre-pay on: 10. März 10. Juni 10. September 10. Dezember These dates are set down in the German income tax law, article 37 (§37 EStG).
You transfer the pre-payments into your local Finanzamt's bank account, in your case Finanzamt München (they have several accounts at different banks, just choose whichever takes your fancy), stating as the reference your Steuernummer, the type of tax and for what period you are pre-paying, e.g. 145/345/404595 ESt. II/2012 if "145/345/404595" is your Steuernummer, ESt. is Einkommensteuer (= income tax + Soli), and you are pre-paying the income&solidarity tax payment for the second period of 2012, due by 10. June 2012.
The numbering is I (= 10. March), then II (= 10. June), then III (= 10. September), then IV (= 10. December).