Manual Offline Conversion Tracking in Google Ads

Hi

Here is the process at the moment

1. Someone clicks on Ad, lands on a landing page and fills in a lead form (this is done with Unbounce)
2. Email gets sent to us with a gclid and the user's details
3. We create a Gsheet for the client with all the leads, the details including the gclid, date & time, enquiry. The client then update with a value and whether it resulted in a sale

>> I need someone to guide me through how to upload the values manually for the moment back into Google Ads.
If we can do this on a video call that would be brilliant.

thanks
Michael