For learning Sanskrit language it is necessary to know alphabets in Sanskrit. You have to know alphabets in Sanskrit to learn writing in Sanskrit language. Sanskrit alphabets are the building blocks of Sanskrit language. There are 52 characters in Sanskrit alphabets. Sanskrit alphabets are made up of Sanskrit vowels and Sanskrit consonants. The Sanskrit alphabets contain 16 vowels and 36 consonants. Sanskrit vs German gives a comparison between Sanskrit and German alphabets.
Sanskrit script is also known as Sanskrit writing system or Sanskrit orthography. The set of visible signs used to represent units of Sanskrit language in a systematic way is called Sanskrit Script. The Sanskrit language uses Devanagari i.e. Sanskrit alphabets are derived from Devanagari script. The script decides the writing direction of the any language, hence the writing direction of Sanskrit is Left-To-Right, Horizontal. Learn Sanskrit Greetings where you will find some interesting phrases.
Is Sanskrit hard to learn? The answer to this question is that it depends on one's native language. One should start learning Sanskrit language with Sanskrit alphabets and Sanskrit phonology.
Time taken to learn any language that is mentioned here is the approximate time required to learn specific language for the person who is proficient in English. You can also go through all Indian Languages and find if Sanskrit is one of the language of India.