First thing to do is to import the video of the explosion into After Effects (I got the video of the explosion from: https://vfx.productioncrate.com/search/#!/ultimate+explosion). Once the explosion has been imported, track the spot where the explosion is going to go with a Null and attach the explosion to it and place the explosion where it is desired.
Once the explosion has been placed, stretch the footage by right clicking on the layer and selecting "time stretch". Then type a number high than 100 The higher the number the longer the video will be stretched (I set mine to 200). Once that is done, cut the first part of the explosion and duplicate the layer and have the initial part of the explosion that was cut from the original and set it to 100 (the default) as seen in the image below and then pre-compose those layers. This will give the explosion some life as the initial explosion will be fast then it will slow down as it expands and gets bigger.
Then apply the levels effect to the explosion layer.
In the levels effect, set the channel to red and same with the scene channel (the 3 circles coloured red, green and blue located in the options bar above the timeline and just under the scene). And then use the layers to match the shade with the ground that the explosion in on and do this for all 3 colour channels. This should then make the explosion fit the ground. In this case, it makes the explosion smoke look a bit dustier so it fit the desert colour.
Once the explosion matches the scene, create a new copy of the explosion (which will be used to create the shockwave of the explosion) and apply a simple chocker effect to it and set it so that none of the off shoot stuff are visible and that it is tightly around the explosion itself.
After the simple chocker has been applied, add a fast box blur and leave it (for now) and add a levels effect, change the channel to alpha and set the alpha white input to 1 and then go back to the blur effect and animate it using keyframes so that the explosion starts off clear the becomes blurry and turns into a bubble as it expand.
Once that is done, create a new duplicate of the original and change the track matte mode to inverted alpha matte and add a second fast box blur. Create a new adjustment layer and a bubble effect and use it to make the shockwave more rounded.
Once the shockwave has been created, go back into the main composition and add an adjustment layer and place it underneath the shockwave explosion and change the displacement map layer to shockwave (this will get rid of the colours on the shockwave and make it look see through so it looks like a heat wave being shot out from the explosion) and change the values so that an appropriate result is achieved. If the edges aren't quite right, add a motion tile and change the values until the edges are fixed.
