Maybe this will help.
Here are the 3 sets that are important.
Recast: These two are for the position of recast. When you cast a spell or use an ability it'll make a timer for those recasts
<recastX>800</recastX> This is how far from the left edge of the screen it will be. Larger number will be farther right.
<recastY>100</recastY> This is how far from the top edge of the screen it will be. Larger number will be farther down.
Buffs: These two are for the position of buffs. When you get a buff casted on you, it'll show up here.
<buffsX>1000</buffsX>
<buffsY>100</buffsY>
Custom is only for ones that you manually enter or run and some plugins use them.
<customX>380</customX>
<customY>350</customY>
You won't want these all at the same spot or it could get a bit messy. But I'd just start with recast at first.
Just remember that like I and Arcon have said, we can't say what will work for you as we don't know your screen resolution. I could say a pair of number based on the assumption that your screen is 1920X1080 but if you're on a smaller screen, they might be right off the edge of the screen for you.