Hi Kedar, this is a difficult trek and not to be done solo, you should go ahead with a trek organiser to do this trek. You can check t his travelogue and plan your trek https://www.tripoto.com/trip/summited-stok-kangri-431072
It's a 20 km expedition from trekking point and there is three camp first one is Changma camp which is 3 hours walk from trekking point and next one is Mankharmo camp which is again 3 to 4 hours walk from the Changma camp and the final camp is Base Camp which is again 3 hours walk from mankharmo camp .....
you can reach base camp in two days or three days ...
plz visit www.ladakhmitra.com