When you wake up, head to the desk and collect the PET. Enter the main room, and speak with Mom, who says that the microwave is broken down. Jack in to check it out.
As the first battle in the game, you will go through the basic gameplay mechanics. In the first battle, you will be instructed to equip both cannons. The cannons will destroy the enemies in one hit if they connect.
In the second battle, you will be instructed in the use of combos, by choosing AreaGrab, combined with WideSword. These need to be entered in the correct order, or the combo won't work. The first chip will claim three squares, giving you better access to the enemies. The second allows you to hit both enemies at once.
In the third battle, you are shown instructions on the last remaining elements of the interface, and about counter hits.
Once all three battles are complete, you will be adviced about the next steps to repair the microwave. You will need a "RcvPatch". To obtain it, you first need to speak with Dad to get 500 zenny, and then jack into your PC.
When you connect to the PC, you will connect to internet. The item you are looking for is the Rcv patch; while you can explore alternate paths for additional Zenny or chips, the quest item is at the end of the main blue path. You should find a Navi by itself, who will sell it to you for 500. Once you have the item, exit and head back to Dad and give him the item to fix it.
You will now need to travel to ElecTown. However, Dad need to take care of something first, giving you time to look around. Speak with the three or four people around, to learn about more basics (e.g. regular chips), and return to the subway station. When Dad returns, you will follow him to Elec Town. After travelling, the only route is to walk down the street, although there is a subchip vendor in the alley to the side.
Continue down the street, until the cutscene starts outside the large building. Once it finishes, you can head around the corner and speak with your friends before jacking in to the stereo. Once inside, go to the left corners to get a new chip, and a regular memory upgrade. Speak with Roll and others, check the suspicious navi, and leave. Dad should return, but mention that he has to go back to work for a trip.
Meanwhile, you will head to the square (further left), and receive news about an upcoming tournament. After learning about it, you can head back, check on the stereo system again to see what the suspicious navi did, and return home. When you return to ACDC town, you can now access the chip store, where you can exchange three surplus chips for one random one.