Creating a Hostage Scenario Map
For any map to function properly, you need to place spawnpoint entities in the game world. The info_player_terrorist and info_player_counterterrorist entities are used to mark where players spawn. You want at least 32 total player spawns for the majority of servers to run your map.
Each team needs to be able to buy weapons where they spawn. To enable this, create a brush the covers the spawn location of one of the teams and give it the tools/toolstrigger material, then tie it to a func_buyzone entity. Don't forget to set the team of the buyzone in its properties. Repeat the process for the other team and both teams should be able to buy weapons.
Add the hostage_entity entity at the points you want hostages to appear. You can add up to 12 hostages.
For each rescue zone you want in your map, create another trigger brush to cover the ground at the rescue area, and tie it to a func_hostage_rescue entity.