Create and Writing into a .tempo file using PowerShell Script with variables passed, a specific format

Question

I would like to create a abcd.tempo file using powershell and want to add the content in the below format :

Startdate:12/06/2020

ParamVar2:RISPA

ParamVar3:MLPL

CNTRY=USA

the above is the targeted format , i need to insert into the abcd.tempo file. Startdate is a variable used and similar to this, other variables as well.

what i meant,Startdate, ParamVar2 , ParamVar3, CNTRY are hardcoded labels and these parameters would be filled with the dynamic values fetched from other code block in my same powershell file.

At present, am able to create a new abcd.tempo file using

new-item -filepath "$myfilepath2createFile" -itemtype File and i added some dummy content inside that. but am not able understand how can i create the similar structure , written above.

2. Another requirement is to call a EXE file from this powershell script and pass anotehr 4 parameters to the EXE Though i used

   Start-Process -FilePath $script:testingexeFile

   am stuck at how to pass the 4 parameters to this EXE