How to change layout settings! Seems a nightmare (unless you know how!!!) ????????

4 bars per line will be very hard with this kind of music.
You can:

1/ Go to Style > General > Bar and change the Bar spacing to 1.00
2/ Go to Layout > Page Settings and change the spatium to 1.5mm (that will reduce all the music) and change the page layout to A4.
3/ Go to Edition > Tools > Add/remove line breaks and Ok.

One last trick,
Right click the first measure > Measure properties > Add to measure number > 34.
Then right click the text you added to fake the measure numbers, select all similar elements, click on "All long notes" to deselect it and press Del to delete all your fake texts. If you want the measure number on all bars, go to Style > general > Header, footer ... and change bar numbers to Interval: 1.

You cannot put 4 measures on every line, measures like the first one will not fit with more than one more like it. Measures 44 and 45 will not go on a line with the measures before or after them unless you shrink everything.

I only did a few things.

1. click the note about pedal and copy it. (it's on the clip board)
2. right click the same note about the pedal, click select all similar items and press delete (gets rid of the extra text)
3. click the first note of the song and paste (ctrl-v) to put the pedal note back
4. right click the first measure and select measure propertied and change "add to measure" to 34 (from 0)
5. Select Style->General... and select "Header,footer,number" and at the bottom click interval and change the number next to it to 1. (This auto numbers your measures).
- optional right click a measure number and change font in the Text Style.. dialog to change all measure number fonts. (I made them 10 and bold)
6. ctrl-A to select the entire song
7. press { (shift-[ ) until the measures shrink and all the measures are on 1 page.

In Coordinates Vibe parts (3) I shrunk it down to allow 3 measures on the first line. Any smaller and you will need a microscope to the the notes. Layout->Page settings... then lower the Scaling staff space. This is really the only other thing you can do to shrink the score any more. I would stick with my (2) version.

Four bars per line is something done for jazz lead sheets and music for children, but would not normally be appropriate for orchestra parts. Most of the time that would be way too few - at four bars per line, a Beethoven symphony could be hundreds of pages long. Other times it would be too many - you can't fit four measures full of thirty-second notes on a line and have it be readable. So you are usually best off just leaving the line breaks alone.

In the example you posted, the layout actually seems not bad to me as is. I mean, it's hard to read, but not because of how it's laid out - those are just a lot of pretty irregular triplets. You can certainly reduce the staff size and/or reduce the note spacing to squeeze another measure one a line here and there, but if you do that I think you'll find it's pretty dense and not any easier to read.

For instance, try Layout / Page Settings and reduce the staff space size to 1.7mm, then select all and reduce stretch two notches (press "{" twice). It will all fit on one page - with some room to spare even - but I don't know that I prefer it that way, personally.

I also find all these flagged sixteenths easier to read if beamed together instead, including beaming over some sixteenth rests.

There is a huge amount of triplets (100%, right? Not a straight eighth to be seen.)
I can't second-guess you or the composer, but this piece would almost be more legible in 6/8 or 12/8.