* Go to your key configures menu (usually in Settings -> Input -> Configure keys).
In there under "Game" group, set keys for "Activate Inventory Item", "Next Inventory Item" and "Prev Inventory Item" to use inventory in game.
* Go to Instant Action
* Select under Custom games list "Unreal 1 game".
* Configure it to a good skill for you, mainly the skill settings:
Game Difficulty level - Easier skill means more health, lesser and weaker monsters. Higher skill level means lesser health, more and harder monsters.
Tourist mode - If enabled, translators will show hint messages.
Use old songs - If enabled, use classic Unreal 1 musics (otherwise part of the musics are remixes).
Auto save game - If enabled, the game will auto-save on start of each map (so you can load next time you want to play it from "Load Game").
* Rather deselect ALL mutators.
* Start game.
To use Translator:
Make sure you have show base path keys (by default M and N keys), otherwise set them in settings.
Press tab and write in command "QuickSave" or "QuickLoad". You can aswell bind them to a key using "Set" command, example: "Set Input F6 QuickSave".
At start you only should see 1 map available from instant action menu, start from that. As you beat maps you unlock them into the maplist and make them playable.
You can normally host game from Host Game (this has full coop support). Some coop play settings to notice:
Servers list - Under which games list server should appear in (by default on coop games list).
Required kill % - How many percent of monsters needs to be killed on the map before map can be ended (to prevent players from rushing through maps).
No movers blocking - Disallows players/monsters from blocking doors/elevators.
Show ends - Shows ending icons (in case if some players dont know where the ending area is).
Monster Spree - Show killing spree messages for monsters.
Player Spree - Show killing spree messages for players.
Monster players - Allow players take control of monsters (useage: press Tab and write "PawnList", then select a pawn with command "SetPawn").
Finish game on last map - In case if some map is unable to load, end the game (and start mapvoting or w/e).
Force U1 Weapons - Replace any UT2004 weapons/ammos on maps with unreal 1 weapons/ammos.
Spawn location type - Custom player spawn area.
Broadcast Prelogins - Show a message whenever someone is about to connect to the server (still needs download files etc.).
Show monster deaths - Show death messages for monsters.
Auto adjust skills - Auto-adjust monster skills based on amount of players.
Weapon respawn time - How many seconds does it take for weapons to respawn (0 - No respawn).
Item respawn time - How many seconds does it take for items to respawn (0 - No respawn).
Allow startup weps - Allow players join with current available map weapons.
And the at last but not least:
You are allowed to use any parts of these maps/mods for your own maps/mods!