If there is a template., can you please point out where I can find it.
If you are interested in seeing a template for a test procedure to use a guide or format for other test procedures, I suggest you look at MIL-STD-810H "Environmental Engineering Considerations and Laboratory Tests." You can find a free copy here:
Go through the table of contents and see if anything there looks about right for what you need. Or, I suggest you might want to begin with Part Two "Laboratory Test Methods." Here you will find a couple dozen specific types of environmental tests with very clear guidance and templates. I am pretty sure any one of these could be a good template to follow.
If you still don't find a good template to adopt/follow within MIL-STD-810H, the I suggest you explore the ASSIST database. Go to the ASSIST database: https://quicksearch.dla.mil/qsSearch.aspx and just start searching. To streamline your search Just type “MIL” in the Document ID, select “Active” if all you want are current/valid documents and then go to the Find term box and type in any free text of what you are looking for. A quick search for active MIL type documents containing the term "reliability" found 8 full pages. Some are military specifications, some are military standards and there are other documents as well. After a while you will figure out what you are looking for and my guess is you will pretty quickly find just what you are looking for.