The Mission is a step towards the goal!
The Mission is one step forward towards conditioning our body into reaching our ultimate target, which is to be fit and strong.

 The mission has to be well thought out, it doesn't have to be a huge task but it has to be a task that will ease our body into being active.

Your situation might and will differ, but the crux of it is the same:

1) It has to be something that can fit within your day, causing the least amount of disruption to your life/routine.

2) It has to be something you do enjoy doing, or at the very least, something you do not hate doing.  This is very important, you don't want to force yourself into doing something you hate doing, especially when there are so many things that you like doing.

If you don't like doing anything, then find something you don't hate doing, I guarantee that as time passes by your enthusiasm will grow, you will find enjoyment where you previously couldn't see any.

One other thing that's of foremost importance is that whatever you decide to do, don't do anything that might hurt your body.

Also, you are NOT interested in any quick results as those are fake shortcuts that usually lead to nothing and if unlucky they lead to:

Disappointment >  Not fun and it  stops us from getting ahead which would vanify our efforts done so far which would  take us back to where we started from.

And since we DO want to achieve results as fast as we possibly can, we therefore DO NOT want to waste time by taking what at first seems faster  but in the end works out to be a slower path to achieve our goal.

Btw if this was to happen, and by this I mean we mess up in some way that after doing so well we somewhat find ourselves 10 or 1000 steps back from where we started from.. hey that's still ok. It is important to understand that:

1) Losing a battle doesn't equate to losing a war

2) We are humans and make mistakes

3) Sometimes what we see as mistakes are actually necessary steps that we have to take in order for us to get ahead.

4) There's a positive to every negative. A mistake is simply a necessary evil in every learning process. In other words, making mistakes forces us to find a solution to the mistake, this process makes us stronger in that we learn that whatever happens,  we are NOT stopping because of a mistake o 10 mistakes. Eventually when making a mistake, instead of dwelling on it by kicking up a fuss or (worse) giving up we simply learn to take it on our stride and we peacefully find a way to bypass it in order to go ahead, towards our goal.

In some cases  I might know from past efforts that before getting it right I have to get it wrong at least half a dozen times. In these cases, I might even welcome one or two mistakes as I know that  this necessary process is leading me closer to getting it right.

Getting back to the mission, depending on your body, or rather how overweight you are, be careful not to choose something that's too hard on your body, you don't want to hurt yourself, we want to simply build a mild calory burning habit, so at first it has to be something fairly light.

For instance if you are too heavy and start off by running, you will place unnecessary stress on your legs, spine, heart, so don't do any running.

A mission could be anything that burns calories that can be quantified so that you can then stick to it and do it every day and after a couple of weeks you start to get  various benefits from it.

Once you choose your mission, the mind set will be something like this: I will carry on doing everything that I am doing. I will keep on eating everything I eat, I can even eat MORE if I so require, BUT there is just one tiny tiny condition that no-matter-what I must stick by: my mission.

My mission is the only thing that matters, so long as I do my mission each and every day, I can then be free to do whatever I want, eat what I want just like before I started this mission.

As I said above, there might be (hopefully very rare) occasions where we will fail on the mission. There are ways to make up for it, depending on what the mission is.

Setting a mission while thinking that you are going to fail it isn't going to do you any good.  If you feel like you are going to fail your mission, just set a very easy mission and that's it. The main point here is to learn to stick to a mission in order to then experience ourselves what happens when our body gets accustomed to doing something and it gets into an automated mode till the point that the mission is nothing, the mission has become our life and as such it isn't a mission any more, it is something we like doing and look forward to doing it even if we don't have to.

Of course we might not get to enjoy all our missions but at least in my case it has not been so, I sometimes replaced one mission with another but in the end, the reason I have always wanted to get fit is because being unfit simply sucks in a very major way.