In your grf(Only apply if you are using kRO's data/rdata.grf)
translation/custom/optional are up to you, you don't really need them unless you are. Your RO Client will run flawless unless a file not found on kRO's data is encountered(Outdated as such).
clientinfo.xml(Must)
book(Optional/translation related)
lua files/luafiles514(Optional/translation related)
palete(Optional)
sprite(Optional/or if Custom Sprite related.)
texture(Optional/translation/custom related)
msgstringtable(Translation related/ Must-ish)
2011-03-15Ragexere/ 2012-04-10Ragexere, also you could use Shin's Diff for these clients
or 2013-08-07Ragexe, I used the xdiffsomething patcher to patch my Ragexe(s) since its simple.
you don't really need a tutorial or some sort, coz' you could use search/or browse through stuff.
http://herc.ws/board/topic/164-requested-links/