Quoteyou comment out stuff in php by putting two slashes in front of the code. To get rid of the login link, find
addbutton($sys_menu_buttons,'{LOGIN_LNK}','{LOGIN_TITLE}','{LOGIN_TGT}','login','');
and replace with
// addbutton($sys_menu_buttons,'{LOGIN_LNK}','{LOGIN_TITLE}','{LOGIN_TGT}','login','');
You're not meant to copy everything from the sample theme, but only the stuff you want changed.
Is it possible to copy everything in /themes/sample/theme.php to my own theme /themes/HCP/theme.php, then remove or change the things I don't want?
possible, but we recommend the other way round: Copy only the stuff you want to see changed from the sample theme into yours.
Sorry for asking such a stupid question, but I want to confirm this; I copy any code I want changed (the whole section of it) into my own theme without replacing anything?
yes