TTC after miscarriage, how to chart with irregular periods

I had a miscarriage in April, it finally completed in June due to retained tissue. I have had spotting 1 week before my period up until it starts since the miscarriage. Any one have a similar experience? I'm also curious how to chart my periods on these apps, should I count the first day of spotting as CD 1 (period day 1) or do I start when the flow is red like a normal period?