Open your Tiller Foundation Template

Navigate to the Categories sheet

If you haven't already, expand the budget month columns

Select column E and hold the shift key and then select column P. This assumes that column E is the first month you have set and P is the last month you have set.

Right click and choose “Insert 12 right” to insert 12 blank columns to the right of the current budgeting year’s month columns. 

Use the fill handle to pull and fill the contents of the month for the last year into the 12 blank column headers. This should create 12 new budget months. The budget months should be formula driven and look like this =eomonth(E1,0)+1 where E1 in the formula is the previous month's cell.

Use the fill handle to pull and fill the contents of your category budgets for the first category in your list from left to right. If you want to start fresh with new budget amounts for the year manually enter values in the first month and fill to the right from that month instead.

Hold shift and select all the cells for the 12 new months for the first category (that you just filled across to the right). Hint: you can select the first one, hold shift, and select the last one to the far right and it will select all 12. 

Use the fill handle to fill the formulas down to all your category budget rows for the new year.

Optionally: hide columns from the previous year when the new year starts so those don’t get in the way. Click the column header letter for the first month you want to hide, hold shift, and then right click the last month you want to hide and select the "Hide columns ... " option.

Plan out your budget for the new year by entering budget amounts into the cells for each category in the new months.

Open your Tiller Foundation Template

Right click any tab along the bottom and choose "unhide" to unhide the "New Year" sheet

Hold shift, select, and right click to copy the 12 months of the new year from the New Year sheet

Navigate to the Categories sheet

If you haven't already, expand the budget month columns

Right click into the first empty cell in row 1. This should be directly to the right of your last budget month. Usually in column Q.

Choose "Paste special > values" - this should expand the table boundary out to the right. There will be a small icon in the lower right corner of the last new month cell at the bottom of the categories list. It's important that the table boundary expands.

Hold shift and select all the empty budget target cells for the new month columns (row 2 and below) and change the format to Currency from the Format menu in the middle of the Home ribbon. Do not change the format of row 1.

Use the fill handle to pull and fill the contents of your category budgets for the first category in your list from left to right starting with the last month. If you want to start fresh with new budget amounts for the year manually enter values in the first month and fill to the right from that month instead.

Hold shift and select all the cells for the 12 new months for the first category (that you just filled across to the right). Hint: you can select the first one, hold shift, and select the last one to the far right and it will select all 12.

Use the fill handle to fill the formulas down to all your category budget rows for the new year.

Optionally: hide columns from the previous year when the new year starts so those don’t get in the way. Click the column header letter for the first month you want to hide, hold shift, and then right click the last month you want to hide and select the "Hide columns ... " option.

Plan out your budget for the new year by entering budget amounts into the cells for each category in the new months.