There is no real answer to this question.

So firstly there is no real solid platonic form of medieval combat. The experience of the anglo saxon fryd, is different to the experience of a housecarl, is different to a mounted nomadic archer, is different to a mercenary Italian crossbowman. How you fight, why you fight, and what fighting looks like for you changes with culture, class, time period, how well rested and supplied you are, region and motivation.

So what can we know? We can put together first hand accounts and grander historical accounts. Here is an excerpt from The memoirs of Bernal Diaz del Castillo a conquistador. The below can be combined with a knowledge of what the general armaments and their overall situation of both sides were with the human element.

" Day now began to dawn, and we emboldened each other to meet the coming severe conflict by putting our trust in God and commending our cause to him, while every one was determined to defend himself to the utmost. As soon as daylight had fully broken forth, we perceived more troops of armed natives moving towards the coast with flying colours. They had on their feather-knots, and were provided with drums, bows, lances, shields, and joined themselves to the others who had arrived in the night. They divided themselves into different bodies, surrounded us on all sides, and commenced pouring forth such showers of arrows, lances, and stones, that more than eighty of our men were wounded at the first onset. They next rushed furiously forward and attacked us man to man: some with their lances, others with their swords and arrows, and all this with such terrible fury that we were compelled also to show them earnest. We dealt many a good thrust and blow amongst them, keeping up at the same time an incessant fire with our muskets and crossbows; for while some loaded others fired. At last, by dint of heavy blows and thrusts we forced them to give way; but they did not retreat further than was necessary, in order that they might still continue to hem us in in all safety; constantly crying out in their language, Al calachoni, al calachoni; which signifies, kill the chief! And sure enough our captain was wounded in no less than twelve different places by their arrows. I myself had three; one of which was in my left side and very dangerous, the arrow having pierced to the very bone. Others of our men were wounded by the enemy's lances, and two were carried off alive; of whom, one was called Alonzo Bote, the other was an old Portuguese.

Perceiving how closely we were hemmed in on all sides by the enemy, who not only kept constantly pouring in fresh troops but were copiously[Pg 11] supplied on the field of battle with meat, drink, and quantities of arrows, we soon concluded that all our courageous fighting would not advance us a step. The whole of us were wounded, many shot through the neck, and more than fifty of our men were killed. In this critical situation we determined to cut our way manfully through the enemy's ranks and make for the boats, which fortunately lay on the coast near at hand. We therefore firmly closed our ranks and broke through the enemy. At that moment you should have heard the whizzing of their arrows, the horrible yell they set up, and how the Indians provoked each other to the combat, at the same time making desperate thrusts with their lances. But a still more serious misfortune awaited us; for as we made a simultaneous rush to our boats, they soon sunk or capsized, so that we were forced to cling to them as well as we could; and in this manner by swimming we strove to make the best of our way to the small vessel, which was now in all haste coming up to our assistance. Many of our men were even wounded while climbing into the vessel, but more particularly those who clung to its side; for the Indians pursued us in their canoes and attacked us without intermission. With the greatest exertions and help of God we thus got out of the hands of this people.

After we had gained our vessels we found that fifty-seven of our men were missing, besides the two whom the Indians had carried off alive, and five whom we had thrown overboard, who had died in consequence of their wounds and extreme thirst. The battle lasted a little longer than half an hour. The spot where it took place was certainly called Potonchan. Our seamen, however, gave it the name of Bahea de mala Pelea, (the bay of the disastrous engagement,) as it stands on the maps. As soon as we found ourselves in safety we returned thanks to Almighty God for the preservation of our lives. Our wounded, however, had still great sufferings to undergo, as we had nothing but salt water to wash their wounds with, which caused them to swell very much. Some of our men swore most bitterly against our chief pilot Alaminos, and the conduct he had pursued; he having steadfastly maintained that this was an island and not a continent. I must, however, break off here, and relate what further happened to us, in the next chapter."

http://www.gutenberg.org/files/32474/32474-h/32474-h.htm

In a limited sense you can also see what parts of combat are like by trying them yourself. Some HEMA clubs and reenactment groups do larger scale combats or skirmishes to try to recreate these. However please be aware that these cannot and will not actually capture what it feels like to march 3 days, have little to eat and fight an enemy who are very motivated as you are attacking them.

As Iamalittledrunk says, there's no singular answer to the question. However, you might find this answer from a few years back by /u/Hergrim interesting - it's written from the perspective of a 12th century knight on his first cavalry charge.