Agatha Christie - Murder on the Orient Express

This is a Help for this chapter because I found this one a little be tricky.
I give not all clues but a help for those who are stuck.

In Walid's bedroom, take the paper with the line with december to complete. You have to add 1 to next line and next column from previous line.
So the answer is : 5 1 9 3

To translate the code with the computer in Walid's living room write : RAPFE

So in Walid's office, the code is : E3F9P1A5R

Account number is : 82664

In Walid's office you have a pyramid with some holes, these holes must be the same as the magnet on the fridge. Then tou can open the drawer. With the pencil passed over the sheet to reveal a symbol.

At least, the dartboard. Using the chess you know that 3 pawns are white and 3 others black.
They are :
black : A8 / A7 / B7
white : D8 / A6 / D5

Then you can "open" the dartboard.
There is a strongbox. This one have 7 digits to put.
According to the sheet in the office you have tu put the code as the picture describe the track on the numeric keypad.
So start with a 4 1 5 3 6 8 #
The strongbox is open ! take the key.

Call your teammate and chapter is note really done but the end is so much easier.
At the bank, go downstairs and in the room look right and go to locker 4346
Used the 2 keys.
And put the safe code : 34962