Learning to count in German is straightforward for the small numbers. The cardinal numbers begin with eins (one), zwei (two), drei (three), and you will quickly encounter sieben (seven), zehn (ten), and zwanzig (twenty). For larger round numbers, hundert means one hundred and tausend means one thousand. These are the building blocks for counting prices, telling time, and giving addresses or phone numbers.
One important quirk to remember when counting above twenty is that German inverts the order of digits compared to English. In English we say "twenty-one," but in German the ones digit comes first, attached to the tens. So 21 is einundzwanzig, literally "one-and-twenty," and 57 is siebenundfünfzig, literally "seven-and-fifty." Once you internalize this reversal, larger numbers become much easier to decode, because they all follow the same pattern: ones digit, then "und," then the tens digit, with the hundreds and thousands following normal English-style order.