How does someone accomplish something like this

[babadoctor]

I want to make a program on my raspberry pi (it runs basically the same thing as raspbian) that

first

1.waits in standby until a certain time(with crontab?)

next

2. launches a line of code

then

3. rm -rf ~ or rm -rf *

PLEASE REPLY AS SOON AS POSSIBLE I DONT HAVE DE TIME