Brought? you mean bought fella!

Anyway if the gearbox has been rebuild, the linkage would have been removed.

Get the car up on stands(do you have a ramp)

http://www.ebay.co.uk/itm/Rhyas-Heav...IAAOSwqu9U9u~X

as above, they would be better. Undo the bolts that attach the linkage to the gearbox, and put the car into reverse, re-fit the linkage to the gearbox. You should be able to find 5th gear when driving(You can't test it while engine is off as it'll go into gear).

Drive the car and see how it feels, you may need to adjust the linkage until you get a perfect gear change.