missing files

i went to start up my game to day and it wouldnt load so i went indepth and it said these files are missing
37.53155|I|verifyHash| lua\common\websocket\bit.lua: missing
37.53157|I|verifyHash| main.cs: missing
37.53158|I|verifyHash| shaders\common\postFx\smaa\SMAA.h: missing
37.53160|I|verifyHash| ui\entrypoints\creatormode\css\bootstrap-social.css: missing
37.53161|I|verifyHash| ui\entrypoints\creatormode\css\bootstrap.min.css: missing
37.53162|I|verifyHash| ui\entrypoints\creatormode\css\font-awesome.min.css: missing
37.53163|I|verifyHash| ui\entrypoints\creatormode\js\flot\jquery.flot.js: missing
37.53164|I|verifyHash| ui\entrypoints\creatormode\js\flot\jquery.flot.selection.js: missing
37.53165|I|verifyHash| ui\entrypoints\creatormode\js\flot\jquery.flot.time.js: missing
37.53167|I|verifyHash| ui\modules\apps\RadialMenu\app.js: missing
37.53169|I|verifyHash| utils\editor\html\css\bootstrap.min.css: missing
does any one know how to fix it thx

 

When you boot up the game, if you bought it on steam, there's a "Verify Integrity" option. Click that, and steam will add any missing files.