Check the mission details to see what system the deadspace complex is in. Travel to that system (if necessary) by using stargates and/or the autopilot. Once in the correct system, right-click in open space and at the bottom of the menu, below Agent Missions:, you will see a menu item for your mission. A submenu will include an option to warp to the complex gate.

Another method is to close and re-open the tutorial. If you are in the correct system, you will be prompted if you want to warp to the complex.

Finally, the following is from an in-game helpful bio:

If you're here, you probably need to get back to the Deadspace Tutorial Complex to continue the tutorial. Just follow the instructions below:

In order to get back, you must be in your home system. This is the first planetary system that you start in. When you are in the home system (read below if you aren't sure) then continue on.

When you are sure you're in the right system, view the left sidebar, the Neocom. Near the bottom, you will see a button that says Tutorials, with a picture of a white face. A new window should appear with a list of tutorials. Click on the first option, Aura : Tutorial. When the tutorial window appears, you will automatically be warped to the Deadspace Tutorial Complex. You should now be at the tutorial area.