1)timing is easy you just have to set the eng at TDC on cylider one(use screwdrive in plug hole one to check piston is fully up or check that rota arm is pointing towards plug lead one and then make sure timing marks are aligned) double check timing marks are aligned.
2)mark all pulleys to be safe so if you move them you can move them back.
3)undo tensioner,remove belt from top pulleys so you can now remove head.
4)when refiting check that all marks line up spot on,make sure the main of the slack in the belt is down the longest clear stretch of the belt,adjust tensioner until belt can only be twisted 1\4 of a turn\twist in the middle of the longest part of the belt and tighten nut.
5)turn crank at least 2 full engine cycles to make sure it all turns over ok by hand(easier with all plugs out due to compression stroke) make sure all marks realign when done.remember one tooth out and it wont run right all marks must align spot on.
6)check belt tension again.