Hi Francis. I'm not long since qualified either, so there'll be others who can tell you better, but I'd say it's totally down to you to judge. From my experience I'd suggest you'll understand when to do it after a game where it all boils over a little, so when you do have a 'bad game', do treat it as a learning curve as opposed to something that puts you off.
I used to kids coaching and in my first 6-7 games as manager we won every game convincingly. I didn't enjoy it because I was finding out very little about the kids in relation to where I could develop their game. Refereeing is much the same for me. Of course it's glorious when you get paid £20/£30 for a 90 minute run with little incident but you'll often learn a lot more from the nightmare games!
Dealing with the comments above for me would depend entirely on the nature of the game. You've ignored it in this instance, and the game hasn't boiled over at any point. It sounds like you maintained control, and that could be in part down to the fact you've not given the players a sense of injustice to boil over about by talking to or cautioning them for a comment that they can simply argue is a disagreement over a decision or decisions that you've made.
However, if the game was taking a different direction, and your decisions to allow play to continue where there was a nibble at an ankle or a late challenge etc was to begin to cause confrontation and friction between the two sides or increasing the quantity and/or heading towards these comments getting more direct and personal, you might decide to use that actually in this instance, your cards are your friend. Stamping it out early with a booking will often lead the rest of the team, or both sides, to understand that you're not going to suffer fools gladly.
But, equally, just as useful can be your decision to purposely slow the game down. It's something that I myself struggle with, but done effectively it's brilliant refereeing. Forcing a ceremonial free-kick (not allowing a quick one and ensuring you take your time putting the wall in place etc) can really take the heat out of a game where it's about to boil over.
Equally, taking someone for a very-much public talking to with arm gestures galore and maybe even a captain present can show the rest of the players you're not messing about and will often interpret the warning as one they should heed themselves, too. As I say, these are approaches I don't have much experience of implementing and I need to work on my own game in relation to not allowing myself to be flustered in higher pressure situations, instead taking my time and cooling the game down in doing so.
But again, I'd reiterate that your decision making in which of these approaches to take will all come with experience. The more matches you rack up, the easier you'll be able to identify patterns in which direction a match's behaviour is taking. On this occasion, I'd argue you handled it quite well. If in future you're feeling confident, give the players a bit back or let them know your glasses are in the dressing room and you'll get em at half-time. Showing you're a human and approachable can earn some respect.
