Need a knot experts help please.

Tie two ropes together and it's called a blood knot. Check out Youtube.

Add/reduce length as needed.

Focus on the bad 50%.......

Triple overhand represents the holy trinity...... The power of Christ compels..... Er, ah, I mean The Father, The Son and the Holy Ghost

I would help but not going to be on the flats for another three weeks.

What are you tying with?

I haven't ever made a rosary, but it sounds along the same lines as knotting a pearl necklace- and I've done that before. The trick is fairly easy: when you have your loop, take the smallest screwdriver you have and put it in the center. As you pull the ends of the rope (SLOWLY,) you can use the blade of the screwdriver to 'walk' up the loop to where you need it to be. Scoot the loop up, pull the ends of the string to start closing the knot, scoot it some more if you need to. Take a few minutes and use a practice piece to see how you can get control of the knots' placement. You'll find that you can even move the knot a little when it's closed lightly upon the screwdriver blade, if you're careful enough.

Does that make sense?

And the fingers are tying...?

Leather? Paracord? Hair?

3,4,5mm?

Color?

Not the color of your hands.

What The Grey told you is a good technique. I will generally just walk the knots up to each other, gradually tightening as I go to snug them up with each other.