Does your TV use IR or bluetooth for remote control? Try searching for "raspberry pi IR remote" or "raspberry pi BT remote" and you will see lots of hits. I'd start there and find one that looks suitable to you. If you get stuck on something, ask!
You can schedule a program to execute at your desired time using 'cron' and set up the schedule using crontab (https://linux.die.net/man/5/crontab
I haven't tried this so I cannot make a specific suggestion.