How the Number of Decimals Affect the Settings?

1934.352 - 1933.308 = 1.044 about 1000 points.
1933.308 - 1932.308 = 1.000 exactly 1000 points.

Point is the smallest value the EA sees on a chart.

if you have 0.001 on a chart, then 1000 points means 1.000
if you have 0.01 on a chart, then 1000 points means 10.00

Conclusion:

If your broker shows XAUUSD for instance 1780.xxx “Three digits”, Distance, Max Spread and TP values should look as follows:

Distance 1000
Max Spread 5000
TP 1000
Series TP 1000

The above is equivalent to:

If your broker shows XAUUSD for instance 1780.xx “Two digits”, Distance, Max Spread and TP values should look as follows:

Distance 100
Max Spread 500
TP 100
Series TP 100