Instructions:

\ 1. Create a new world. You can use the Customise World feature to make a world that you think will optimise your run, but leave ore distribution in their default settings. Creative Mode. Enable cheats.

\ 2. Download this folder, unzip it and paste that folder into the folder that has the same name as the world you just made. [Need help finding it?]

\ 3. Give yourself a structure block and place it, doesn't matter where as long as it's above y=32. This will become your new world spawn but this is not the starting position of your speedrun. Each team will be teleported to a new random location in the world when the game begins.
/give @p minecraft:structure_block
\4. Put the structure block into Load Mode and type in these numbers in the three boxes under where it says Relative Position. -3, -29 ,-2. Do not change the orientation of the module.

\ 5. Choose which speedrun you would like to do and input its title into where it says Structure Name. The options are:

SRhealth
Objective: Drink a Potion of Healing II as fast as possible. It
has to be a strong healing potion, so a lucky witch drop will not be
the end of the game.
Rules: No natural regeneration, hard difficulty, constant night vision.

SRcure
Objective: Feed a golden apple to a zombie villager affected with weakness. You do not have to wait for the villager to be cured.
Rules: Eternal Night, hard difficulty, constant night vision. If you decide to change difficulty, remember that villagers are more
likely to become zombies in harder difficulties.

SRguardian
Objective: Kill three elder guardians as fast as possible. If you decide to change biome settings, remember ocean monuments only occur in Deep Oceans.
Rules: No starvation damage, hard difficulty, constant night vision.
Sidebar: The number of elder guardians each team has killed will appear in the sidebar.

You can change any gamerule that isn't mentioned in the rules, and hard difficulty is only the default; it can be changed. The module will look like one of these:

\ 6. All players who want to participate should choose a team. The options are Blue, Pink, Green and Yellow. To join these, just press the coloured buttons on the module. The white button is to leave your team. If you aren't on a team when the game starts, you will spectate. Do not press the button in the middle yet.

\ 7. The button in the centre of the module starts the game. Do not press this button until you are ready to begin the game. All participates will be put into Survival Mode automatically.

\ 8. The time appears in the action bar. It should always be there if the game is going. The timer will stop when all teams have completed the speedrun.

\ 9. At the end of the speedrun, you'll see FinishTime in the sidebar, which is how long the speedrun took in seconds.

\ 10. Leave feedback in this thread of how the game went and any technical difficulties you had. Did you have fun?

Happy speedrunning!