Could not assemble hello.asm

i got this .asm file "hello.asm":

segment dseg
msg:    db      'Hello, Dear World$'

segment sseg stack
        resb 0x40

segment cseg
..start:
        mov     ax, dseg
        mov     ds, ax
        mov     dx, msg
        mov     ah, 0x09
        int     0x21
        mov     ah, 0x4C
        int     0x21

the problem is that i was unable to properly compile it with NASM, im pretty sure there is nothing wrong with the code, its just that i couldn't figure how to use NASM

it yields this:
C:\NASM\NASM HELLO.ASM
hello.asm:1: segment name `dseg' not recognised
hello.asm:4: segment name `sseg' not recognised
hello.asm:7: segment name `cseg' not recognised
hello.asm:8: unrecognised special symbol `..start'