how to use something like if and else in batch

@echo off mode 1000 goto block1

:block1 echo color goto block2

:block2 pause set /a num=%random% %%5 goto 0

:0 if num == 0 goto a goto 1

:1 if num == 1 goto b goto 2

:2 if num == 2 goto c goto 3

:3 if num == 3 goto d goto 4

:4 if num == 4 goto e goto 5

:5 if num == 5 goto f goto 0

:a color 0a goto block2

:b color 0b goto block2

:c color 0c goto block2

:d color 0d goto block2

:e color 0e goto block2

:f color 0f goto block2 i want to make a color sign witch changes colors and i would like use simething like this . but i cant use else in batch and it would need something like that