i have no idea what 당신 mean 의해 this and that. 당신 will know when to play up 또는 down when there is a slur 또는 a marking up 또는 down bow. generally pieces that start on the first beat start down and if it is a pick up it is usually up bow. to express notes, 당신 can lean on them 또는 add vibrato .
hope this helps i've been playing violin for 8 years ( private lessons) so i think 당신 can trust me