Firstly always draw the Boundaries (Plot plan) correctly in CAD never trace them.
1.Surveyor. Get the data file of the Surveyor and import it into chief is the easiest (this way any errors ( if any) are on him).
2 Second Way. Firstly draw the Boundaries correctly in CAD, Then scan as a JPG, a Survey plan, or Screen grab ( windows snipping tool) a scaled Topo plan off the council web site etc. Import the JPG into CAD detail in Chief, Expand it out to match your correctly dimensioned site plan, trace the Topo lines as CAD lines, Don't forget a north arrow for when you turn it later. I usually do this in a CAD window, Group them into a layer, then copy to Main plan. AS it is grouped at this stage position it, turn it to suit your plan and relationship the the dwelling. Then Convert CAD lines to elevation lines and set the heights manually. This should be quite accurate in 3d.
3. IF ALL else fails. Go out with a dumpy level. Set a datum point. ( manhole cover or some fixed point.) Take a lot of strategic Heights. Essentially what the builder does when he sets the site out.
NOTE: The accuracy and accountability fall towards you as you go from 1 - 3
Done all 3 LOL. Number 3 as late as last week which was a small addition/deck for a friend not worthy of expensive surveyors charges. Datum Point was the house floor level.
Good luck