to access first letter u use strng[0], second letter strng[1]
While this will work in C for a char array it will NOT work in lite-c.
STRING is defined in atypes.h as
typedef struct STRING {
C_LINK link;
char *chars; // pointer to null terminated string
long length; // allocated length of string
long flags; // see STRF_... above
byte pad[PAD_STRING];
} STRING;
Therefore you must access the character data as (strname.chars)[index]. The first character is index = 0 etc. Just remember that STRING* is not the same as char*.