index/match return data from one sheet to another

Hi All
Can anyone help me with a formula please...

I am unsure if this will be an index/match or sumproduct formula or even something else.

I have a “cost trend” sheet which I need a formula in the red highlighted cells which will pull data from the summary tab.

These are the matches:

• Cost Trend Sheet match rows 5,17 and 29 with cell B1 on the “Summary” sheet (Match the Month)
• Cost trend sheet match rows 6, 8 and 30 with columns C and D on the “Summary” sheet (Match the Actual or Budget)
• Cost Trend sheet match column C with column B on the “Summary” sheet

The formula will only work for one month at a time – it needs to be zero if it’s a different month to cell B1 on the “Summary” sheet

Any suggestions how best to achieve this? I can not change any data on the “Summary” sheet.