No Clue where to start: Importing Excel file into existing oracle tables

Question

I have an excel document that has data organized in formats according to the columns of tables we have. Our database is 10 G and developers only have clients such as toad to manipulate database.
There are two columns that are sequentially created using tbl.NEXTVAL in two different tables. They are called LEAD_ID and CUSTOMER_ID in LEADS and CUSTOMER table obviously these are not included in the file.
CREATE tbl CUSTOMER ( int CUSTOMER_ID, varchar(40) FirsName, varchar(40) LastName )
CREATE tbl LEADS ( int LEAD_ID, int CUSTOMER_ID, varchar(40) notes, varchar(40) status )
The excel file is organized in cells that is consistent..
Where do I start, how would I do it? and I am being asked to do it by tomorrow and I have no clue..Can I do this with oracle itself or I have to read the file through Java?
Please give me some idea
Thank you,

Answer 1

Thanks for your suggestion with checking the log and bad file..It helped and was able to insert..
Actually this is a real project.. and the actual data is in the hundreds or more.. The problem was I had put sysdate in double quotes and should have been without them. It is now inserting into the table.. however If I can ask one more question.. I have actually multiple tables that I need to insert into from an excel file which is organized in columns..
For example.. let's say I have a row in the excel file as
Claim_Number FirstName LastName
A single insert would be inserting into four tables (CLAIMS, CUSTOMERS, LEADS, etc..)
first on CLAIMS table that only takes the Claim_Number
Second CUSTOMER table, that takes the Claim Number and Customer names ( FIRST and LAST)
Third could be inserting the LEADS table with a sequenced lead number along with the customer name and claim number..
So I would need to reuse the values three or four times for a single record to be inserted..
Can you give me some idea?
And also I have columns like ACCOUNT_TYPE that would be have same value always more like a constant or other columns like UPPER_FIRSTNAMEwith result that comes from a sql function with Uppse case of the other column.. which is just the upper case letter version of FIRST_NAME column.. and it won't be read from the input file.. How would I take care of such issues like the sysdate .. I tried the following shown in bold but didn't work..
LOAD DATA
INFILE 'c:\trex2.csv'
BADFILE 'c:\trexbad.txt'
APPEND
INTO TABLE CC_CUSTOMERS
FIELDS TERMINATED BY ","
TRAILING NULLCOLS
     LAST_UPDATE_DATE sysdate,
     CUSTOMER_NUMBER "CC_CUSTOMERS_S.NEXTVAL",
     CUSTOMER_ID "CC_CUSTOMERS_S.NEXTVAL",
UPPER_FIRSTNAME UPPER(:FIRST_NAME) ,
ACCOUNT_TYPE CONSTANT 'Residential'
     FIRST_NAME,
     LAST_NAME
Thank you in advance..