If this is like a crossword puzzle using numbers instead of letters, you will need to post a picture image to this website with the clues or take a photo of the puzzle and upload it to the website (perhaps by sending it to the server first).
If you can't do that, you will need to copy the clues and submit them with details of the puzzle like how many rows and columns; where the black boxes are, using a row-column system. For example, if the puzzle has 10 rows and 10 columns, use letters A to J for the rows and 1 to 10 for the columns. Then you can say where the black boxes are by using the reference: e.g., a black box in the top left hand corner would be A1 black; one in the bottom right-hand corner would be J10 black. Or you could just list the blacks: BLACKS in A1, J10, etc.
Then you need to say where the answers go: 1A would mean 1 across; 1D would mean 1 down; so you would write in the ACROSS clues: 1. A2 (5) meaning that 1 across starts in A2 and is 5 digits long; in the DOWN clues: 1. A2 (8) meaning that 1 down starts in A2 and is 8 digits long. It will take you some time and effort to do this, so a picture would be better and you would avoid mistakes.
Anyone reading your description would be able to construct the puzzle themselves from the information, and then go about solving the clues.