can please guide me on how to go HK Space Museum and avenue of stars by mtr from Argyle Street?

To the museum, you can walk where you are to Tsim Sha Tsui Station to take Tsuen Wan line to Mong Kok station. Then get out from exit C2 and you can easily walk there.

To the avenue of Stars, there is only around 500m from Argyle Street, so you can walk there directly.