Need data installation for backtests in MT4 in order to achieve 99,9% quality

Rather than spending hours downloading data from website and then importing it without knowing if that data will be really correct,

I would like to know if a developer can do it eventually on my computer via teamviewer or other application,

OR

Give me easy instruction how to :

-> get data (forex, indices, commodities...)

-> import data 

-> use data for backtests in MT4 in order to achieve 99,9% quality.

It can be a Teamviewer presentation or instructions. Not important. I simply don't want lose time by searching for a solution by myself.