Need Assistance In Interpreting SQL Tuning Advisor Recommendation

 Hi Folks

I was wondering if someone could explain to me (in plain terms) what the SQ Tuning Advisor is telling me here
in 1 and 2

I included the SQL for reference

Any suggestions are welcome

Thannks
Jim

1.
The predicate TRUNC("A"."AUDITDATE")>=TO_DATE(:B1,'yyyymmdd') used at line ID 3
of the execution plan contains an expression on indexed column "AUDITDATE".
This expression prevents the optimizer from selecting indices on table "LLTEST"."DAUDITNEW".

Rewrite the predicate into an equivalent form to take advantage of indices.
Alternatively, create a function-based index on the expression.

2.
The predicate TRUNC("A"."AUDITDATE")<TO_DATE(:B1,'yyyymmdd') used at line ID 3