The role of the dungeon master is not an easy one, especially when your not only the one that enforces rules but also created them in the first place. Your main job is to tell the story, control the npcs, decide, the loot, decide how physics work and to roll the die for almost anything. Anyone who has played dungeons and dragons or any form of tabletop roleplaying game already knows this, so the gist is for you n00b cakes. It's not easy being a dm. More often than not your players will argue with you on what you said, what they can and can't do and get pissed on bade dice rolls. Most of what I'm going to put down here is my own opinion.

Optional gameplay mechanic: The Dungeon Master can make their own characters like the players and be part of the story, however they must treat their own characters no differently than the players' characters, must not make the story focus to much on themselves, and need to make sure they don't meta game, meaning your own characters can't know something without proper explanation. Also your not allowed to solve riddles or puzzles, though with puzzles your allowed to assist players depending on if its a physical goldrube device type puzzle. 

So as a dm, I actually want my players to win, but I don't want it to be easy. Sometimes my players get a little to arrogant and will jump into the fray of any battle when what I need them to do is run away or be strategic. Very often I get complaints that something is too hard, to which I respond, WORK TOGETHER THEN!, and that normally solves the problem. I want my groups of players to all be legendary not one pretentious asshole who thinks he is above the rest. Sometimes I have players take the reigns and try to put in some of their lore or try to do something I didn't say was ok before. Its better to try to prevent this going overboard beforehand instead of resolving it later because the latter of which often leads to arguements. So to prevent this you need to tell your players to talk to you before the next session and see what it is they want to do. If both sides see the other as being unreasonable then you both need to compromise. 

One last note that I want to add here is to make sure that your players say what they are doing before they roll dice, otherwise this can cause people to fudge dice rules. No one must do that, not even the dm, the only exception is if someone gets the same number 3 times in a row, then they have to reroll and stick with the outcome, that does not mean you are allowed to reroll 1s, unless you get 3 in a row. in this game your base rolls are on d20s, which are the only thing you can get fails or crits on which iI will explain under turns. Also the roll DOES NOT COUNT if you roll for someone welse without permission, it flies off the table(tabletop simulator rules) or if hits something. If you are having trouble not having enough romm to roll then get a dice tower or tray.