Ahh help! Maths SAC tomorrow and I can't do these questions!

[littlebecc]

Hey,
I missed out on a crucial double last week and they learned all about trend lines and forecasting. I thought everything was okay but now i have no idea what to do

Heres the question:
The table below shows the deseasonalised washing-machine sales of a company over three years. Use least squares regression to fit a trend line to the data.

No of purchases (deseasonalised) 1     2     3     4
Yr 1                                        53    51   53   55
Yr 2                                        64   64    61    63
Yr 3                                        67    69   68    66

Now, the question before i could easily do it because it just had
year
number of students

But with this one it has numbers (1234) up the top and numbers on the side.

I have no freaking clue what to do and to me honest i'm kind of stressing. If anyone could help...i'll give you a massive online hug. Hahaha;
But srsly. HELP!