This little guide should help you to get these achievements on your way to getting "All Together Now" -
Eye In the Sky
Up and Running
After completing a couple of combat missions, your man in the nifty green sweater vest will notify you that it is time to launch your first satellite. You will be brought to the board showing all countries across each continent. Simply pick a country and press A to launch the satellite. It will take a few game days on the Geoscape to go active but this will put you 2/3 of the way toward the achievement if you started your base in the USA an then chose Canada as your first satellite launch (which also increases your funding by 100/month and will give you the "Eye in the Sky" achievement.
Now, you will only need to launch one more satellite over Mexico later in the game when the option becomes available to pick up your "All Together Now" achievement for having a satellite over every country in a continent.
This one is a bit harder to launch since you have to build some facilities first before you can launch another satellite. You will need to see your engineer about building facilities and excavate some space and build an access lift to go down a level for more building space. First you will have to build Alien Containment which as your first facility will net you the "Up and Runnnig" achievement. Now you will need to build a Power Generator in order to make more facilities. Then the game will force you to build a laboratory first (which will net you the "Theory..." achievement) and then you will need to build a workshop in order to increase your number of engineers since you have to have at least 10 engineers to build the Satellite Uplink required to launch your 3rd satellite. You will wind up needing to excavate more space in the process to free up area to plant each building. Once your workshop is built (netting you the "...and Practice" achievement), you will need to build another Power Generator to give you the power prerequisite needed to build the Satellite Uplink. If you had the money and the space, you could have also built as the workshop was being built saving you some time. Now you will need to build the satellite using your by visiting your engineer and requesting to build item - Satellite. Once it has been completed, visit the Situation Room and launch the satellite over Mexico and this should get you the "All Together Now" achievement.
I recommend saving your game before launching the 3rd satellite since it is strategically a better move to put your satellite in another continent to have your eyes in the sky in other areas of the globe.