writing "Nf3" with "f3" after a little drawing of a horse.
That's Chinese.
馬f3.
That is a glyph for horse. You can see the exaggeration of a mane, 4 legs, and a tail.
lol - yeah I didn't think of it this way, but that kind of makes sense 
Figurine notation is part of a scheme to become "language-less"... [so that] a book publisher can print 1 book and sell it to every country in the world without hiring translators...
This the reason I suspected for figurine notation. I don't know if figurine notation is pgn-scan-able or not as @bong711 thought. If it isn't, then I don't know if this was the main intent of it or a side-effect/bonus.
This may sound silly but after reviewing threats and candidate moves.... sit on your hands.
make this a habbit. it really works
Not only for anxious kids, but also a good tip for many adults: literally sit on your hands. The act of shifting your body weight to move your hands, before you make your move, will remind you to do a blunder check or search for a better move.
Another tip is to simply have fun. Yeah, I know kids probably hear that a lot: however, this also means trying to enjoy the moment. Tell them to take their time and enjoy the game: they might naturally slow down too.
Yup, good advice 
We will talk about time management at camp:https://premierchess.com/virtual-camp-2020
I don't know if this will work, but it worked for me. I was rated about 600-700 uscf last spring, about a year ago. all of the tournaments I went to were 45 minute, no delay. then I went to the 2019 national k-12 tournament. the time control was a shocking 2 hours and 30 minutes! In almost every game I played, I ended the game with less than an hour on my clock. I placed 24th in the U800 section with a 5.5/7 score. at my next tournament, players from opposing teams had commented that watching me play was like watching paint dry. even though this was true, it worked perfectly. I placed 2nd out of about 80 students and I had a perfect score. My reccomendation? take them to a tournament with a longer time control. it doesnt have to be 2 hours, but increasing the amount of time they have will reflect positively on them in the future, especially if they see improvement by using more time.
I think chess benefited our son. He played all sport till high school. I started him playing chess competitively in between sports 8 to 10 tourna ments a year by high school he played only soccer and his varsity chess team. His team won back to back state championships in the 4 A division and one overall state championship. Our idea was just play to enjoy it didn't matter if you win or lost. he was always a straight A student I will always feel chess helped. He didn't play in college he devoted all his time to academics. He did benefit getting a scholarship I believe his academics and chess accomplishments helped. he decide to pad his resume applying to dental school after taking a year off and played in his catagoty at the US Open in Los Vagas. He nearly won his catagoty but lost one game. He only applied to one dental school out of 1400 applicants they accepted 75. At his interview one question they asked him was "are you still playing chess? "
Maybe you tell your children to think what your opponent is up to
for eg here they give him a queen he thinks that they made a blunder,he plays fast,captures the queen and then got checkmated show these 2 traps to him
This happens if you play fast
I used to be on a club and many kids had the same problem, not to blame, kids are a bit rushy, however the antidote was to put them to play all days 60 min games in which yes or yes they have to spend 1 min thinking each move, even if they already knew the move, crazy enough but it work!!
Figurine notation is really the same as in Algebraic notation. It's real purpose in being used is prevent Scanning and Conversion to PGN format.