Start at the Monte Rosa Hütte and hike up the trail leading to the Monte Rosa regular route, first on the moraine then some class 3. When the trail turns left after a short steep section you will be able to reach the Grenzgletscher at the right side (some visible paths, cairns). One should figure out the correct way if one is planning to start by night.
On the Grenzgletscher go up mostly using the left side of the glacier. Be carefull, there are a lot of sometimes big and tricky crevasses, some even along the direction of ascent. Especally at the lower section when a secondary gacier is coming in at the left.
After a steep region of seracs you reach the upper, flat part of the Grenzgletscher below the final rise to the Lisjoch. There you can turn right directly to the begin of the N-Face below the typical half-moon of the Bergschrund.
You'll need about 3 hours from Monte Rosa Hütte.
The Klucker-Neruda Route starts left of the main rock area in the center of the N-Face. The route first uses the snow / ice field below the central rock ridge between two big seracs leading to the E summit of the Lyskamm. The original route then follows the rock ridge up to the final ice field and the summit. This is the most secure way up.
It's also possible to climb at the left or right side of that ridge (it should be more difficult to use the ridge). In this case no rock climbing is needed for the route. Be carefull of icefall from the seracs if you do not use the ridge.
Traversing the bergschrund where ever possible (this is often the most difficult part) and then try to reach the base of the rock ridge as soon as possible. If you have done that you should be out of ice fall danger at regular conditions (what ever "regular " may be). Climb up the ridge himself or climb at the right (or left) side on snow and ice. The route is simply straight foreward.
It will take about 7 hours from the base of the face up to the summit.
Rope, 2 ice axes, ice screws
If one climbs up the rocky ridge you may need stoppers or friends too (a small rack shoul be ok).
It's a good idea to take a bivy at the upper part of the Grenzgletscher near the base of the Klucker-Route. Leave all the bivy gear at the bivy, you can take it with you when you desenct via Grenzgletscher to the Monte Rosa Hütte. It's also possible (but somewhat suffering) to use a tent, this offers a great possibility for some routes in that area (the other 4000m peaks) without usage of the crowded huts.