To explain in layman terms:
Actifit is an fitness rewarding app. You simply have to install the app ,open it, then start your fitness activity . You can see in the app that your activity will get recorded while you are doing your activity. Activity doesn't necessarily have to be any exercise or something. You just go for a evening walk,you walk in home,office or anywhere- everything will be regarded as activity. At the end of the day you have to post your activity to steemit. This option Is provided with in the app. You will get one upvote from @actifit everyday in your actifit post based on your activity and simultaneously you will aslo receive some AFIT(actifit) Tokens.

How are actifit token rewards spread for actifit post authors?
Count Actifit Reward
5,000 to 5,999 20 tokens
6,000 to 6,999 35 tokens
7,000 to 7,999 50 tokens
8,000 to 8,999 65 tokens
9,000 to 9,999 80 tokens
10,000 and above 100 tokens

What will the tokens be used for?
Our plans are to have Actifit tokens available for purchasing fitness related equipment, tools, gadgets, sports wear,... and enable transactions between providers and actifiters. Add to that, we plan on creating gym partnerships for the use of Actifit tokens for paying gym memberships and similar concepts.
And most importantly, once SMTs are launched, Actifit tokens will have their own valuation against STEEM as well as FIAT currencies, and hence can be cashed out for actual FIAT currency.

So what are you waiting for ?? Download the app right away from here https://bit.ly/actifit-app and start getting healthier and wealthier.

Hope this gave you a rough idea on how this app works. Pls don't hesitate to ask if you need further assistance.