To install patch, you would need to refer the Release Notes provided along with the patch.
The Release Notes would normally be named:
(a) ReleaseNote.PTF_<Patch Number>.txt, for e.g. ReleaseNote.PTF_10.0.001.txt (or)
(b) ReleaseNote.D<Patch Number>, for e.g. ReleaseNote.D01.txt where D stands for Debug
A PTF Patch is expected to contain fix to address the issue usually described in the Symptom field in the Release Notes, whereas Debug Patch is usually patch that contains debug library(ies) that outputs debug to log file(s) through which we gather additional data to troubleshoot an issue. A Debug Patch may contain fix as well as described in the OVERVIEW section in the Release Notes.
As a best practice, please create a new empty directory for each individual patch, save the patch files in and run the installation from that directory. PTF or Debug patch installation executable will backup files that are going to be replaced and create uninstall executable in the directory. When you have individual patch directory, it will be easier just in case rollback is necessary.