Hi Apurupa Konathala,
Actually Where do you get that record id ...you manually entered?
This is my idea you can try this to save details from one entity to other
1.In a page pass the PAID PARAMATER and in the button call the second page where you want to select the Record id
2.In that second page use
To select the particular id you can use checkbox
1.Use a boolean attribute
2.In the checkbox select the boolean attribute and in events in on leave choose save changes and Auto-synchronize -yes
3.then in the save button call microflow
microflow-1.Retrieve the record entity
3.in the loop Add decision (Boolean attribute=true)
4.if true then commit
I am adding some screenshots to refer try it
If you are using a many-to-many association, you might want to use the reference set selector. If so, you can eliminate the use of custom microflows. Did you consider using this option?