how do I restart with a different date?

Hi, not sure I totally follow your question

but I started on 12th May and just ount from there

I add it on as I do it , 

so I pick the post training data and add the date amount I run and keep a running total in the update text

Thanks for your answer Michael. I haven't been keeping track of my training data at all! What I meant was that when I started the challenge it asked me when I wanted to start from and then I noticed that it only counted the data I put in since I was on TS, so it looked like I have done nothing before that. When I tried to change the dates on the challenge it just set me up for the challenge twice. Confusing eh!!!!!