You don't need to complete Liara's Mission, but it's not difficult. First she'll want you to hack three secure stations in the Illium transportation area. When you do, there will be a short time for you to find a nearby server. You'll find one station near the entrance to the transportation area, with a destination near the Baria Frontiers kiosk. Another station can be found on the other side of the transportation area entrance. That one leads to a system near the Memories of Illium kiosk. The third station is near the Gateway Personal Defense kiosk and leads to a point near the tracking office. Completing this part of the Mission earns you 40 experience points and 2,000 credits.
When you return to Liara, you can trigger the second phase of the Mission. You'll need to find five datapoints to hack in Nos Astra. The first one is right at the bottom of the stairs to Liara's office. You'll find two more at kiosks in the market, and another at a display in the area. The last datapoint is in the bar in Eternity. Once you have all five datapoints, you can call Liara. The datapoints are a logic puzzle of sorts, and I won't give away the answer. Just remember to think outside the box. Your reward for this part of the Mission is another 40 experience points and 5,000 credits.
When you return to Liara, you can trigger the second phase of the Mission. You'll need to find five datapoints to hack in Nos Astra. The first one is right at the bottom of the stairs to Liara's office. You'll find two more at kiosks in the market, and another at a display in the area. The last datapoint is in the bar in Eternity. Once you have all five datapoints, you can call Liara. The datapoints are a logic puzzle of sorts, and I won't give away the answer. Just remember to think outside the box. Your reward for this part of the Mission is another 40 experience points and 5,000 credits.