There is most likely a place in your game where players can leave the boundaries, especially if they can walk off the edges of your map. You can use a teleporter to bring them back to their spawn points, and get back to playing the game.
teleporterand drag the Teleporter object into your game, and move it below your terrain or wherever you need to reset players.
Next, you will create something for the player to look for, and pick up. You can scatter these randomly, hide them in foliage, or place them strategically to lead a player through your game.
Press Play and try picking up your resource. It should disappear, and the number displayed in the top right should change from 0 to 1.
Right click the Resource Pickup and create a new template. You can drag from the My Templates section to add more to your map. You will use more of these as you continue to build the level.
Add the physical challenges to your map. If your goals are more combat focused, you should add strategic covering and points of interest instead of difficult places to reach. No matter what, you should start with safer places and lead your player to higher risk areas as the game progresses.
Add your first obstacle to your game. This could be a precision jump, or just taking stairs up to a high area. You want to introduce the idea that this is a challenge, without making difficult yet. You can also use visual elements and the collectible resource to bring players to this first important point.
Add a narrow stretch that is difficult to walk across, or a next jump that is more precarious and further away from the ground. The goal of this element is to let players know they are on the right course, and give them a preview of the challenges ahead.
This is the part where you show players a new element that can help them, or guide their strategy as they go through your game. You may want to demonstrate to the player that flying or double jumps are possible by making the next challenge require them, or try adding a Player Launcher object to make them see how they will get to the next point.
This could also be a point to introduce a Weapon or other tool that players can use to get through challenges or win the game.
Your collectible resource is the easiest way to let players know that they have accomplished something. With combat games, a Kill Feed can let them know who they defeated and see their names flash on the screen.
Try using the Finish Line object from Community Content for players that reach a final important point on your map to know that they finished the challenge.
From here, deciding what your game should include is up to you. There are many ways to win or lose games in the world, and how you want your experience to exist is up to you. Keep in mind that you can continue to build new levels and pieces for your game, so the most important thing to do now is to create a complete experience that can be tested by others. The more you test and change your game based on feedback, the stronger it is, and the more ideas you will have for its next phase.