Ok, it looks like you have a users, products, and clients table. You have user relating to clients through a foreign key and the same for products. The thing that this structure does not account for is if the client has multiple products. This structure would be fine for holding a single product, but how would you record the details if the client had multiple products?
I think you could account for this if you had another column in the products table, if you added a client_product id column to this table you could use this as a foreign key to relate to the client directly. The products table would then have an entry for each product the client owned, it would contain the product id, the name of the product and the id of the client.
You could also leave the current structure in place and creating a lookup table for client_products. This table would have three columns, an auto incrementing id column for the primary key, a column for the client id, and a column for the product id.
I think if you add in this extra column or this lookup table you would be able to account for the multiple products per client.