If you act in good faith according to the mission briefing, attacking the two visible turrets immediately with your initial infantry force, and sending your reinforcement group NW to attack the two turrets across the river, you will be disappointed. As soon as the first turret blows up, three friendly Gunboats show up, only to be sunk instantaneously by a heavy laser as they approach the Nod base. You might as well ignore the mission briefing and just play the scenario normally.
You shouldn't need detailed instructions for this scenario, but there are a few points worth noting.
1) Don't suck the near Tiberium patch completely dry so that it can replenish. The one further south, across the river, can never be exhausted completely, because it has two Blossom Trees.
2) Nod attacks you with waves of about 10 infantry units plus a mobile artillery unit. You will not be able to fight them effectively with infantry; you will need tanks plus APCs.
3) You should build a wall to limit access to your base. The AI cannot shoot at walls, so force it to enter your base through a narrow channel to make overruns easier.
4) When you have worked up to a force of 10 tanks and 5 APCs, your army can hold the field against anything Nod can throw at you. At this point, feel free to blow up the Nod Harvesters, which eventually do come out to play. Then you will run Nod out of money, and then you can dismantle the Nod base at your leisure.
5) You may decide to do a brute force attack into the Nod base while they still have an income. In that case, you will take heavy casualties. If you do this, make sure to capture the Construction Yard first, and then the Hand of Nod and then the Airstrip. This will eliminate the Nod production, even if they still have an income.
6) You can certainly do a deliberate assault. The northern approach has the advantage that it keeps away from the laser, but it may be hard to use infantry due to the Tiberium patches. The eastern approach has the advantages that you can employ your infantry, and the supply line is shorter. However, you will need to pay close attention to the laser. It turns out that, while the laser kills a Gunboat with one shot, it needs at least two shots to kill a tank! Don't expect to find any money in the Nod Silos after a deliberate assault. This means that it is not cost-effective to capture Silos in this situation.
7) You can blow up all the Power Plants from outside the range of the laser. Then you can attack the laser with impunity.
8) After capturing the Airstrip, you can produce mobile artillery units, which are only useful against small groups of infantry. You can also produce flamethrower tanks, which are deadly to infantry and buildings. You can also produce the other units that you already know about.
9) After eliminating the Nod base, you turn your attention to the turrets located on the river. This time, your Gunboats manage to navigate the river safely, but they never do anything! They just move back and forth and act as targets.
10) There is a crate containing $2,000 in the very SW corner of the map. Just touch it with a unit to collect. You would never find it if someone didn't tell you to go there, because there is no strategic reason to go there.
11) You will not get Airstrikes until the Nod base is eliminated. However, in this scenario, you may still need to blow up some turrets at that point, and the planes can help with that. They actually do significant damage to turrets, and if they can't be repaired, it matters.
12) After eliminating the second turret on the south side of the river, you get a transport helicopter.