Spare the isolation work until you have atleast 16" arms...
First, get overall size, make sure to todo close grip benches, i started with them to late, after ten years of training because i did not get a good pump from them as pushdowns etc.the make arms thick, and also improve bench.
Do them and dips as a part of a chest routine. Low rep and heavy... Actually those are my main chest execises too..
For biceps, make sure to have undercrip pullsdowns or pullups on back day...similar to close grip bench for biceps..
Then later in the week have a arm day if you like with curls and frenchpresses... Or add isolation after chest and back depending on split.
I spent too much time hunting for bigger arms, but nothing else.. The first inch came in weeks, then i stagnated for years until i finally got into dc training. No longer doing that, but it made me learn things.
I have naturally big chest, which makes chest training a breeze, but arms sucked...now they match..
Secret... Do less for arms, but mote often, they cant take much work per session, but they are small so they recover again very quick..
Sample splits.
Arms
Shoulders
Legs
Back
Chest
Chest back
Shoulders arms
Legs
( important to have a restday after chest back)
Or do
Chest back
Legs
Shoulders arms
Rest
Repeat
The classic
Chest shoulders triceps
Back biceps
Legs
Rest repeat or repeat the two upperbody days... With different rep range then rest two days and repeat.
My favorite for some time
Chest triceps
Back biceps
Shoulders triceps
Legs biceps
Dont go overboard with arm,6-9 sets each time... It works better todo arms with 12-20 sets spread over two workouts rather than one
But until you have gained 1-2 inches, stick to the more basic splits with just 1-2 isolation moves with few sets... Youll not regret it