How do I add my period?!?!

Hi lovely ladies! I'm totally new to this app so bare with me! I want to add my period on the tracker but for the past 4 days it's only given me 'spotting' as something to track. I've been filling that in thinking it was my period section but now it's Coke up saying I've been 'spotting' for 4 days which could be sign of an infection!!! But it's meant to be my period! 
When I go to the calendar it says to move the pink dots in the right place but I have none! When I try and add my start date it says I can't add one so close to my existing period start date?!?!!
Help! Totally confused!!