The Clarkson/Cherry family of Grahamstown

If you have no family tree software installed,
you could do worse than the free software from MyHeritage:

http://www.myheritage.com/family-tree-builder

Then download the data
by right-clicking this link and choosing the 'save as...' option...

download the family tree data

Opening the saved GED file ought to fire up MyHeritage and load the data.
If it asks any awkward questions along the way evade them as best you can.