theres a Select Recommended next to Apply Selected, also theres a few Patch that has (recommended) next to its name.
i'd say do the latter and check what was instructed on the guide.
when enabling Patch Name "Enable Multiple GRFs (Recommended)" it ask for a DATA.ini name just leave it as it is, you just need a data.ini file in your RO folder.
if youre new i'd advice to use an older client just so you know that your client/server is working and then try experimenting with newer clients. somewhere 2013-2015, 2014-10-22bRagexe is perfect for new players.