Update tutorial.md
Update tutorial.md

Line 159: changed "this" to "these"
Line 411: added instruction for clarification
tyduptyler13/ejs,zensh/ejs,insidewarehouse/ejs,mmis1000/ejs-promise,operatino/ejs,zensh/ejs,TimothyGu/ejs-tj,kolonse/ejs,insidewarehouse/ejs,rpaterson/ejs,TimothyGu/ejs-tj,kolonse/ejs,cnwhy/ejs,mde/ejs,jtsay362/solveforall-ejs2,xanxiver/ejs,cnwhy/ejs