Vedas are primary scriptures of Hindus.
Upanishads are the philosophical part of Vedas.(last part)
Vedanta(end of vedas/last part) means the Upanishadic philosophy. It is not just the upanishads but all texts related to it. Among the 6 schools of Hindu philosophy(shad darshanas), this is one, called Uttara Mimamsa.
Puranas are mythological scriptures which explain the teachings of the Vedas and Vedanta to common people in the form of stories.
Shastra means ‘That which commands’ … they are authoritative texts…
There are 18 shastras
6 Vedangas(not to be confused with Vedanta. They are texts which support the Vedas)
Nirukta(meaning of words)
Kalpa(procedure for rituals)
Dharmashastras(these are law books like Manu Smriti, Yajnavalkya Smriti etc)
Nyaya(another darshana, deals with logic)
Mimamsa(Purva Mimamsa, another darshana, explains the meaning of Vedas)
These 14 are called Dharma Sthanas (Abodes of Dharma) …
Other than this, there are 4 more Vidya Sthanas(Abodes of Knowledge)
Grantha means a book… a big work, not little texts.