The following example will show you how to setup an automatic lead-convert process with a custom convert criteria.
The following auto lead convert process does not create duplicate contacts / accounts (it uses the lead’s email & company name to find existing contacts & accounts – similar to our mass convert actions).
You can disable/enable the auto-duplicate detection and the creation of new opportunities (disabled by default)…
Creating an automated lead conversion process with a custom convert criteria with process builder / flows:
