There are numerous videos online about UV/vis spectroscopy

e.g. https://www.youtube.com/watch?v=O39avevqndU

Not sure what you mean by "chemical water." You can look at bulk solvents with UV-Vis, but the spectra are well know for the most part and can be found online or at the NIST database. If you are looking for chemicals in the solvent then that is quite doable as well. (Use the solvent as the reference).

which chemicals you want to identify in water first explain then add the chemicals of known concentration in water as reference used both reference and sample runs on uv visible spectrophotometer. using distilled water as a blank.

To measure UV-Vis absorption spectrum, subtraction of a spectral background is always necessary. For the measurement of pure acetic acid, you can use the empty cuvette as the reference.

Thanks everyone Hugh J Byrne, Saeed Ayaz Khan, Ying-Jen Shiu, Nicholas Edward Schlotter.