1. Open the console.
2. Enter in Command: map cp_powerhouse
3. Select Blue Team and Sniper
4. Enter in Command again: mp_autoteambalance 0; mp_teams_unbalance_limit 0; mp_timelimit 0; mp_idledealmethod 0; mp_winlimit 0; tf_bot_keep_class_after_death 1; tf_bot_add 15 blue scout easy
5. Have fun and good luck.
Thanks to stfN1337