They started out with small trade missions, then came some missionaries and so called geographers trying to map the whole thing out. Charter companies then basically started the process and back in the day of "flag follows commerce" they got backing from the Government. They basically had companies listed on the stock exchanges whose main assets were colonies. King Leopold and some German ruler I forgot then organized the conference to carve the continent up because Leopold knew he did not have the muscle to compete when the Germans, French and British came. They had a series of "treaties" too they signed fraudulently to take over and then spent a good number of years putting down rebellions from the local population. However Europe was always fighting and it did not take long for them to plunge themselves and the world into major wars which gave rise to nationalist movements.