Copying data over to a master record

I am trying to build a spreadsheet that would copy data from a packing slip over to what I am calling a master record. I envision a macro that would copy the data from pslip (tab) to Master Records (tab), each time I would press the macro (perhaps a button on the pslip tab) I would like for it to copy the packing slip data to the next available or open column on the Master Records tab. I have the rest of the pretty simple spreadsheet working but can't figure out how to get Excel to copy data to the next available column (and to keep it there as a mater record once it is deleted from the order or packing slip).

My wife wrote a children's book about a new kid moving into a new classroom and I intend to use this to track sales. If the book starts to sell well we'll need to invest in a real book keeping program, in the meantime I was hoping to get by with this. Any suggestions are welcome and to the person who solves it - let me know if you want a copy of the book and I will ship you a complimentary copy along with our thanks.

Any suggestions welcome.