Being mostly a student of armour and weapons history, I can't speak as much to the recruiting/training piece. I spoke about how armies were equipped from the 14th to the 16th century here. Keep in mind that the political organization and economics of the later middle ages and earliest modern period are pretty different from the earlier Middle Ages, so this is an answer only for that later period.

/u/MI13 wrote a good response about the training of urban militias here which may help answer your question about training.

Members of the upper classes at least would generally be responsible for their own day to day training, and results likely varied. The 13th century Scandinavian "King's Mirror" spent a short section describing how a nobleman serving as a king's guard should train, which included practice sparring twice a day with extra heavy weapons and armor, wearing armor whenever they need to travel somewhere by horse, and learning how to shoot javelins, slings, and bows in their spare time with either hand. It was also recommended to collect and learn how to use as many different types of weapons as possible.