If you are trying to figure out how to learn Hindi phonology, there is little that I can explain to you in a written blog post. You should refer to your Hindi course materials to listen to the audio files to learn the different sounds. But there are a few things that you can read about with respect to Hindi phonology. They will help you in your efforts how to learn Hindi.
As in other languages, the vowels have long and short sounds. In addition, Hindi vowels can also be nasalized. A nasalized vowel is indicated by a dot over the letter.
There are two ways of writing each vowel. The dependent version is the version of the letter used when it follows a consonant. The independent version of the letter is used when a vowel begins a word or follows another vowel.
In Hindi, consonants can be either aspirated or unaspirated and either dental or retroflex. For example, the dental “t” sound is pronounced with the tongue touching the roof of the mouth and the back of the teeth. This is further forward along the palate than the sound is made in English. The retroflex “t” sound is pronounced with the tongue touching the roof of the mouth farther back on the palate than in English. An aspirated consonant is pronounced with an audible expulsion of breath. No breath is heard when an unaspirated consonant is pronounced.
Learning languages requires careful listening and imitation to vowel and consonant sounds. Take the time to listen to the audio materials in your Hindi course. If you are taking a university course, go to the language lab. If you are taking an online Hindi course, listen to your audio files.

