To train nades bring up console on an offline map and:

Paste: sv_cheats 1; sv_infinite_ammo 1; sv_grenade_trajectory 1; mp_startmoney 60000; sv_showimpacts 1; sv_grenade_trajectory_dash 1; sv_grenade_trajectory_thickness 1; mp_roundtime 60;mp_roundtime_defuse 60;mp_restartgame 1; god;

After paste: give weapon_smokegrenade; give weapon_flashbang; give weapon_molotov;