Need if/then statement to turn off auto calculation of fields

Brand new .pdf creator/ JavaScript code writer here. I am building an invoice document and have already set up certain fields to auto calculate a total cost. I have it set up so that when values in columns H and J are entered, the product is shown in column K (below right). However, what I need to do is allow for manual entry in all three columns if the 'yes' radio button is checked under the heading of Block (below left). All fields are in the same document, but I do not know how to write the if / then statement so that it reads the Block field values and acts upon them (if that makes any sense). I appreciate any and all help.

Thanks so much,

Amy