How do I convert minus figures to braket figures?

In Excel Goto your Menu bar
Click on Format
Click on Cell
Scroll down to UserDefined( could have a slightly different description-- my machine is German)
In the small field enter the following
#.##0,00;(#.##0,00)

you can change the commas and periods around to suit your formatting.

Then press OK

Then use this new Format to reformat the required Cell

If you want the figures also to be in red then add this [RED] in front of the bracketed figures in the format setup function.

You might also find that your machine already has this format

"=abs()" command

If you mean converting negative integers into their absolute values, then use
=abs()
if your data is in column (A) starting in row 2, then copy and paste the formula
=abs(a2)
from b2 to the end of your data set.

Hope that helps