For those who are a little more hands on with their astronomy.
https://iss-sim.spacex.com/
Works in Seamonkey, but the controls display wrong.
Works in Firefox.
No idea on Chrome or derivatives, not on my system.
It takes a while to load and to play, be patient.
I found that alignment first, then position, works better.
In real life it is also easier on the equipment.
Fly the numbers, ignore the view, which is really really hard.
Rotation, Yaw, Pitch is what I settled on.
Use the controls on the right, these adjust alignment through the center of the craft.
You are lining up your docking ring to theirs, the flatter they are to each other, the better.
It will look off target once aligned, but don't panic
If you have Pitch, Yaw and rotation, all you have to is adjust X,Y,Z.
That alignment is for docking position, not your current one.
The simulator tends to put you low and to one side, just like real life does.
Once you have alignment, you begin working on 3D space position.
The better the preparation you do up front, the fewer last minute adjustments are needed.
It drifts out of position as you orbit, don't panic, that is what happens.
Each object in orbit has its own set of characteristics.
Even orbiting beside each other, they rotate in orbit differently.
Thus pitch, yaw and rotation can drift over time, in addition to x,y,z.
If you are low, you will speed up, that can be confusing, since your closing speed increases.
If you are high, you slow down, which is also confusing, because your closing speed decreases.
Every single adjustment and movement in orbit, effects the other alignments.
Just remember that the simulator/game simplifies what the astronauts actually do.
Its controls are repeatable, but in real life, each adjustment is just a tiny bit different than the last.
Closing speed can be high, even in the red at first, but slow down as you close in.
The closing speed changes color, keep track as you adjust.
Gentle corrections work better than quick ones, let inertia do its job, you have time.
You don't have to be perfectly lined the whole time, just when close.
Drifting into position is fine, as long as the drift is gentle.
Good luck.
Janus.