Step 1
Getting a keyboard that is compatible with the PC you are using is critical to jumping so go and get one at a local store where electronics are sold.
Step 2
Load up Garry's Mod to do this simply open steam hover over library select games find Garry's Mod launch it then select start new game select the map you would like then start the game by pressing the large green button in the lower right hand corner of the window

Step 3

Press the long rectangular button at the bottom of your keyboard known as a 'Space Bar'

If you have followed these steps you should be jumping like a pro!

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