Earlier this year I began working with a 14 year old, who was just finishing his freshman year of high school. He had some basic weight room knowledge with things like Goblet squats, push presses, lunges, pullups and the like.  His technique was decent, but I could tell that the coaching was minimal, so a few things still needed to be refined.

I decided to teach him more of the bigger barbell movements (since he had basic patterns down) so he could get stronger, put on a little size, improve his vertical, and be proficient enough to lift with the team when the time came.

We trained 3 days a week. I was also battling with other conditioning sessions and basketball skill work, so things were modified as needed.

Here's the general layout with some notes about each day.

Monday was squat day. Since I knew he'd be fairly fresh from the weekend, I wanted to take advantage of that and work more technical things.

A. Some type of jump

B1. Squat (waved back squats and box squats as well as utilized the safety squat bar too.)
B2. Upper back or prehab exercise

C1. Lunge variation (walking, reverse, bulgarian, landmine, overhead, etc)
C2. Overhead press variation (DB, push press, arnold, landmine, etc)

D1. Hip hinge (RDL, single leg RDL, reverse hyper, etc)
D2. Varied upper movement (upper back, triceps, row, pullups)

E. Abs/calves/stretch/roll

Wednesday was an upper focus with lighter lower body since he was probably sore from Monday.  We also did sleds on Wednesdays.  Sometimes we did dragging before the weights, especially if he was sore and needed a good warm up. And sometimes we did the sleds after weights (heavier) and did both lower body dragging and upper sled stuff.

A. Upper body med ball work (chest pass, overhead throw, etc)

B1. Bench press
B2. Upper back

C1. Step-up or single leg squat
C2. Back/pull/row

D1. Hamstring curl (band, slide board, stability ball)
D2. Varied upper (pushups, pullups, arms)

E. Sleds (see note, either before or after)

F. Abs/stretch/roll

Friday was made into a deadlift day.  He had never done deads before so we started off with the trap bar for a few weeks then transitioned into some regular deads off blocks then from the ground.  Worked lateral movements as well as a press movement and some more back and posterior chain.  (Fridays were often the ones that got adjusted due to skill workouts he had.)

A. Varied box jumps (seated, regular, weighted, single leg)

B. Deadlift (varied, see above)

C1. DB press (flat, incline, unilateral, alternating)
C2. Back/row/chin-up

D1. Lateral single leg (lunge, step-up)
D2. Hamstring curl

E. Varied based on energy, soreness, etc (arms, upper back, knee prehab)

F. Abs/core/calves/roll

Some weeks things changed based on his schedule and other factors, but generally speaking this was the template I used for 4 months. It helped that he already had a decent squat pattern and understood body positions and how to hinge. Without doing any "speed" work, we improved his 5-10-5 time and increased his vertical jump 3.5 inches.

Nothing magical and nothing overly complex.  The main focus here was to TEACH the movements so he was proficient when lifting with his school's team.  The big lifts were waved starting with a linear progression then moved to some more "dynamic" work.  At 14 years old with not a ton of Barbell training prior, I didn't see the need to max out.  Certain weeks, I was able to push a little heavy on the main movements as long as his form (and focus) was solid.

With a young training age, improvements are almost guaranteed. So education, injury prevention and a balanced program was the goal.